merged Post's YAML front matter into its to_liquid payload, just like Page does. allows {{ page.arbitrary_yaml_data }} (cleaner than {{ page.data['arbitrary_yaml_data'] }})

lib/jekyll/post.rb

@@ -142,12 +142,11 @@ module Jekyll
     #
     # Returns <Hash>
     def to_liquid
-      { "title" => self.data["title"] || "",
+      self.data.merge({ "title" => self.data["title"] || "",
         "url" => self.url,
         "date" => self.date,
         "id" => self.id,
-        "content" => self.content,
-        "data" => self.data }
+        "content" => self.content })
     end
   end