Allow static files in collections

Allow Documents to be static files so static files can exist in collections

lib/jekyll/document.rb

@@ -80,12 +80,19 @@ module Jekyll
       %w[.sass .scss .coffee].include?(extname)
     end
 
+    # Determine whether the document has a YAML header.
+    # 
+    # Returns true if the file starts with three dashes
+    def has_yaml_header?
+      !!(File.open(path, 'rb') { |f| f.read(5) } =~ /\A---\r?\n/)
+    end
+
     # Determine whether the file should be rendered with Liquid.
     #
     # Returns false if the document is either an asset file or a yaml file,
     #   true otherwise.
     def render_with_liquid?
-      !(asset_file? || yaml_file?)
+      !(asset_file? || yaml_file?) && has_yaml_header?
     end
 
     # Determine whether the file should be placed into layouts.
@@ -93,7 +100,7 @@ module Jekyll
     # Returns false if the document is either an asset file or a yaml file,
     #   true otherwise.
     def place_in_layout?
-      !(asset_file? || yaml_file?)
+      !(asset_file? || yaml_file?) && has_yaml_header?
     end
 
     # The URL template where the document would be accessible.
@@ -189,7 +196,7 @@ module Jekyll
           unless defaults.empty?
             @data = defaults
           end
-          @content = File.read(path, merged_file_read_opts(opts))
+          @content = File.open(path, "rb") { |f| f.read }
           if content =~ /\A(---\s*\n.*?\n?)^(---\s*$\n?)/m
             @content = $POSTMATCH
             data_file = SafeYAML.load($1)