allow user to prevent layout render

lib/sinatra.rb

@@ -363,6 +363,7 @@ module Sinatra
     end
     
     def determine_layout(renderer, template, options)
+      return if options[:layout] == false
       layout_from_options = options[:layout] || :layout
       layout = layouts[layout_from_options]
       layout ||= resolve_template(renderer, layout_from_options, options, false)

test/haml_test.rb

@@ -137,6 +137,20 @@ context "Haml" do
 
     end
     
+    specify "can render with no layout" do
+      layout do
+        "X\n= yield\nX"
+      end
+      
+      get '/' do
+        haml 'blake', :layout => false
+      end
+      
+      get_it '/'
+      
+      body.should.equal "blake\n"
+    end
+    
     specify "raises error if template not found" do
       get '/' do
         haml :not_found