diff --git a/middleman-cli/lib/middleman-cli/build.rb b/middleman-cli/lib/middleman-cli/build.rb
index 737d70f8..b8744673 100644
--- a/middleman-cli/lib/middleman-cli/build.rb
+++ b/middleman-cli/lib/middleman-cli/build.rb
@@ -84,7 +84,6 @@ module Middleman::Cli
     end
 
     no_tasks do
-
       # Handles incoming events from the builder.
       # @param [Symbol] event_type The type of event.
       # @param [String] contents The event contents.
diff --git a/middleman-core/lib/middleman-core/application.rb b/middleman-core/lib/middleman-core/application.rb
index 42e50f77..c222123c 100644
--- a/middleman-core/lib/middleman-core/application.rb
+++ b/middleman-core/lib/middleman-core/application.rb
@@ -319,6 +319,29 @@ module Middleman
       config[:environment] == key
     end
 
+    # Backwards compatible helper. What the current environment is.
+    # @return [Symbol]
+    def environment
+      config[:environment]
+    end
+
+    # Backwards compatible helper. Whether we're in dev mode.
+    # @return [Boolean]
+    def development?
+      environment?(:development)
+    end
+
+    # Backwards compatible helper. Whether we're in production mode.
+    # @return [Boolean]
+    def production?
+      environment?(:production)
+    end
+
+    # Backwards compatible helper. The full path to the default source dir.
+    def source_dir
+      Pathname(File.join(root, config[:source]))
+    end
+
     MiddlewareDescriptor = Struct.new(:class, :options, :block)
 
     # Use Rack middleware
diff --git a/middleman-core/lib/middleman-core/core_extensions/data.rb b/middleman-core/lib/middleman-core/core_extensions/data.rb
index 87fd77af..2f866ac0 100644
--- a/middleman-core/lib/middleman-core/core_extensions/data.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/data.rb
@@ -33,7 +33,7 @@ module Middleman
 
         # Setup data files before anything else so they are available when
         # parsing config.rb
-        app.files.changed(:data, &@data_store.method(:update_files))
+        app.files.on_change(:data, &@data_store.method(:update_files))
       end
 
       def after_configuration
diff --git a/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb b/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
index 0a79c3bb..dc179d41 100644
--- a/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
@@ -35,7 +35,6 @@ class Middleman::CoreExtensions::DefaultHelpers < ::Middleman::Extension
 
   # The helpers
   helpers do
-
     # Make all block content html_safe
     def content_tag(name, content=nil, options=nil, &block)
       # safe_content_tag(name, content, options, &block)
diff --git a/middleman-core/lib/middleman-core/core_extensions/front_matter.rb b/middleman-core/lib/middleman-core/core_extensions/front_matter.rb
index c173dccf..f0f6008b 100644
--- a/middleman-core/lib/middleman-core/core_extensions/front_matter.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/front_matter.rb
@@ -27,7 +27,7 @@ module Middleman::CoreExtensions
     end
 
     def before_configuration
-      app.files.changed(:source, &method(:clear_data))
+      app.files.on_change(:source, &method(:clear_data))
     end
 
     # @return Array<Middleman::Sitemap::Resource>
diff --git a/middleman-core/lib/middleman-core/core_extensions/i18n.rb b/middleman-core/lib/middleman-core/core_extensions/i18n.rb
index 8c2b7052..d5dec8e2 100644
--- a/middleman-core/lib/middleman-core/core_extensions/i18n.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/i18n.rb
@@ -23,7 +23,7 @@ class Middleman::CoreExtensions::Internationalization < ::Middleman::Extension
 
     # Setup data files before anything else so they are available when
     # parsing config.rb
-    app.files.changed(:locales, &method(:on_file_changed))
+    app.files.on_change(:locales, &method(:on_file_changed))
 
     @maps = {}
     @mount_at_root = options[:mount_at_root].nil? ? langs.first : options[:mount_at_root]
diff --git a/middleman-core/lib/middleman-core/extensions.rb b/middleman-core/lib/middleman-core/extensions.rb
index 1480091b..fa51796d 100644
--- a/middleman-core/lib/middleman-core/extensions.rb
+++ b/middleman-core/lib/middleman-core/extensions.rb
@@ -64,8 +64,8 @@ module Middleman
           block
         elsif extension_class && extension_class.ancestors.include?(::Middleman::Extension)
           extension_class
-                           else
-                             raise 'You must provide a Middleman::Extension or a block that returns a Middleman::Extension'
+        else
+          raise 'You must provide a Middleman::Extension or a block that returns a Middleman::Extension'
         end
 
         return unless options[:auto_activate]
diff --git a/middleman-core/lib/middleman-core/preview_server.rb b/middleman-core/lib/middleman-core/preview_server.rb
index 646236dc..5b77bbed 100644
--- a/middleman-core/lib/middleman-core/preview_server.rb
+++ b/middleman-core/lib/middleman-core/preview_server.rb
@@ -120,7 +120,7 @@ module Middleman
           end
         end
 
-        app.files.changed :reload do
+        app.files.on_change :reload do
           $mm_reload = true
           @webrick.stop
         end
diff --git a/middleman-core/lib/middleman-core/renderers/slim.rb b/middleman-core/lib/middleman-core/renderers/slim.rb
index c89a99a0..40b44c34 100644
--- a/middleman-core/lib/middleman-core/renderers/slim.rb
+++ b/middleman-core/lib/middleman-core/renderers/slim.rb
@@ -24,7 +24,7 @@ module Middleman
         super
 
         # Setup Slim options to work with partials
-        ::Slim::Engine.set_default_options(
+        ::Slim::Engine.set_options(
           buffer: '@_out_buf',
           use_html_safe: true,
           generator: ::Temple::Generators::RailsOutputBuffer,
@@ -39,7 +39,7 @@ module Middleman
 
         ::Slim::Embedded::SassEngine.disable_option_validator!
         %w(sass scss markdown).each do |engine|
-          ::Slim::Embedded.default_options[engine.to_sym] = context_hack
+          ::Slim::Embedded.options[engine.to_sym] = context_hack
         end
       end
     end
diff --git a/middleman-core/lib/middleman-core/sitemap/extensions/on_disk.rb b/middleman-core/lib/middleman-core/sitemap/extensions/on_disk.rb
index 8d319313..3f58e169 100644
--- a/middleman-core/lib/middleman-core/sitemap/extensions/on_disk.rb
+++ b/middleman-core/lib/middleman-core/sitemap/extensions/on_disk.rb
@@ -24,7 +24,7 @@ module Middleman
 
         Contract None => Any
         def before_configuration
-          app.files.changed(:source, &method(:update_files))
+          app.files.on_change(:source, &method(:update_files))
         end
 
         def ignored?(file)
diff --git a/middleman-core/lib/middleman-core/sitemap/resource.rb b/middleman-core/lib/middleman-core/sitemap/resource.rb
index f7ae229c..b3653605 100644
--- a/middleman-core/lib/middleman-core/sitemap/resource.rb
+++ b/middleman-core/lib/middleman-core/sitemap/resource.rb
@@ -42,12 +42,22 @@ module Middleman
       # @param [Middleman::Sitemap::Store] store
       # @param [String] path
       # @param [String] source_file
-      Contract IsA['Middleman::Sitemap::Store'], String, Maybe[IsA['Middleman::SourceFile']] => Any
+      Contract IsA['Middleman::Sitemap::Store'], String, Maybe[Or[IsA['Middleman::SourceFile'], String]] => Any
       def initialize(store, path, source_file=nil)
         @store       = store
         @app         = @store.app
         @path        = path.gsub(' ', '%20') # handle spaces in filenames
-        @source_file = source_file
+
+        if source_file && source_file.is_a?(String)
+          source_file = Pathname(source_file)
+        end
+
+        if source_file && source_file.is_a?(Pathname)
+          @source_file = ::Middleman::SourceFile.new(source_file.relative_path_from(@app.source_dir), source_file, @app.source_dir, Set.new([:source]))
+        else
+          @source_file = source_file
+        end
+
         @destination_path = @path
 
         # Options are generally rendering/sitemap options
diff --git a/middleman-core/lib/middleman-core/sources.rb b/middleman-core/lib/middleman-core/sources.rb
index 8819e387..493c6bc0 100644
--- a/middleman-core/lib/middleman-core/sources.rb
+++ b/middleman-core/lib/middleman-core/sources.rb
@@ -19,7 +19,7 @@ module Middleman
     attr_reader :app
 
     # Duck-typed definition of a valid source watcher
-    HANDLER = RespondTo[:changed]
+    HANDLER = RespondTo[:on_change]
 
     # Config
     Contract None => Hash
@@ -114,7 +114,7 @@ module Middleman
         [priority, n]
       end.reverse.freeze
 
-      handler.changed(&method(:did_change))
+      handler.on_change(&method(:did_change))
 
       if @running
         handler.poll_once!
@@ -134,7 +134,7 @@ module Middleman
     #
     # @param [SourceWatcher] watcher The watcher to remove.
     # @return [void]
-    Contract RespondTo[:changed] => Any
+    Contract RespondTo[:on_change] => Any
     def unwatch(watcher)
       @watchers.delete(watcher)
 
@@ -233,16 +233,53 @@ module Middleman
     # A callback requires a type and the proc to execute.
     CallbackDescriptor = Struct.new :type, :proc
 
-    # Add callback to be run on file change
+    # Add callback to be run on file change or deletion
     #
-    # @param [nil,Regexp] matcher A Regexp to match the change path against
+    # @param [Symbol] type The change type.
     # @return [Set<CallbackDescriptor>]
     Contract Symbol, Proc => ArrayOf[CallbackDescriptor]
-    def changed(type, &block)
+    def on_change(type, &block)
       @on_change_callbacks << CallbackDescriptor.new(type, block)
       @on_change_callbacks
     end
 
+    # Backwards compatible change handler.
+    #
+    # @param [nil,Regexp] matcher A Regexp to match the change path against
+    # Contract Maybe[Regexp] => Any
+    def changed(matcher=nil, &block)
+      on_change :source do |updated, _removed|
+        updated.select { |f|
+          matcher.nil? ? true : matches?(matcher, f)
+        }.each do |f|
+          block.call(f[:relative_path])
+        end
+      end
+    end
+
+    # Backwards compatible delete handler.
+    #
+    # @param [nil,Regexp] matcher A Regexp to match the change path against
+    # Contract Maybe[Regexp] => Any
+    def deleted(matcher=nil, &block)
+      on_change :source do |_updated, removed|
+        removed.select { |f|
+          matcher.nil? ? true : matches?(matcher, f)
+        }.each do |f|
+          block.call(f[:relative_path])
+        end
+      end
+    end
+
+    # Backwards compatible ignored check.
+    #
+    # @param [Pathname,String] path The path to check.
+    Contract Or[Pathname, String] => Bool
+    def ignored?(path)
+      descriptor = find(:source, path)
+      !descriptor || globally_ignored?(descriptor)
+    end
+
     protected
 
     # Whether a validator matches a file.
diff --git a/middleman-core/lib/middleman-core/sources/source_watcher.rb b/middleman-core/lib/middleman-core/sources/source_watcher.rb
index 834fa0a9..faea6874 100644
--- a/middleman-core/lib/middleman-core/sources/source_watcher.rb
+++ b/middleman-core/lib/middleman-core/sources/source_watcher.rb
@@ -172,7 +172,7 @@ module Middleman
     # @param [Proc] matcher A Regexp to match the change path against
     # @return [Set<Proc>]
     Contract Proc => SetOf[Proc]
-    def changed(&block)
+    def on_change(&block)
       @on_change_callbacks << block
       @on_change_callbacks
     end
diff --git a/middleman-core/lib/middleman-core/version.rb b/middleman-core/lib/middleman-core/version.rb
index 102d7a65..7f92da1d 100644
--- a/middleman-core/lib/middleman-core/version.rb
+++ b/middleman-core/lib/middleman-core/version.rb
@@ -1,5 +1,5 @@
 module Middleman
   # Current Version
   # @return [String]
-  VERSION = '4.0.0.alpha.2' unless const_defined?(:VERSION)
+  VERSION = '4.0.0.alpha.3' unless const_defined?(:VERSION)
 end
diff --git a/middleman/lib/middleman.rb b/middleman/lib/middleman.rb
index 878b9c59..01b9aa97 100644
--- a/middleman/lib/middleman.rb
+++ b/middleman/lib/middleman.rb
@@ -2,3 +2,6 @@ require 'middleman-core'
 
 # Make the VERSION string available
 require 'middleman-core/version'
+
+require 'middleman-sprockets'
+require 'middleman-compass'
diff --git a/middleman/middleman.gemspec b/middleman/middleman.gemspec
index 19d05ffd..ed0acc6f 100644
--- a/middleman/middleman.gemspec
+++ b/middleman/middleman.gemspec
@@ -20,8 +20,8 @@ Gem::Specification.new do |s|
 
   s.add_dependency('middleman-core', Middleman::VERSION)
   s.add_dependency('middleman-cli', Middleman::VERSION)
-  # s.add_dependency('middleman-sprockets', '>= 3.1.2') Disabled in alphas
-  # s.add_dependency('middleman-compass', '4.0.0.alpha.2')
+  s.add_dependency('middleman-sprockets', '>= 3.4.0')
+  s.add_dependency('middleman-compass', '4.0.0.alpha.3')
   s.add_dependency('sass', ['>= 3.4.0', '< 4.0'])
   s.add_dependency('compass-import-once', ['1.0.5'])
   s.add_dependency('haml', ['>= 4.0.5'])