Add support for supplying options to `static!`, enabling the use of custom status codes, etc.

Add test case highlighting the breakage when attempting to use `send_file` with a specific status code. refs sinatra/sinatra#749

lib/sinatra/base.rb

@@ -1015,14 +1015,14 @@ module Sinatra
 
     # Attempt to serve static files from public directory. Throws :halt when
     # a matching file is found, returns nil otherwise.
-    def static!
+    def static!(options = {})
       return if (public_dir = settings.public_folder).nil?
       path = File.expand_path("#{public_dir}#{unescape(request.path_info)}" )
       return unless File.file?(path)
 
       env['sinatra.static_file'] = path
       cache_control(*settings.static_cache_control) if settings.static_cache_control?
-      send_file path, :disposition => nil
+      send_file path, options.merge(:disposition => nil)
     end
 
     # Enable string or symbol key access to the nested params hash.

test/static_test.rb

@@ -216,4 +216,21 @@ class StaticTest < Test::Unit::TestCase
     )
   end
 
-end
+  it 'renders static assets with custom status via options' do
+    mock_app do
+      set :static, true
+      set :public_folder, File.dirname(__FILE__)
+
+      post '/*' do
+        static!(:status => params[:status])
+      end
+    end
+
+    post "/#{File.basename(__FILE__)}?status=422"
+    assert_equal response.status, 422
+    assert_equal File.read(__FILE__), body
+    assert_equal File.size(__FILE__).to_s, response['Content-Length']
+    assert response.headers.include?('Last-Modified')
+  end
+
+end