stop sorting post categories so they show up in order in the url

lib/jekyll/post.rb

@@ -132,7 +132,7 @@ module Jekyll
         "month"      => date.strftime("%m"),
         "day"        => date.strftime("%d"),
         "title"      => CGI.escape(slug),
-        "categories" => categories.sort.join('/')
+        "categories" => categories.join('/')
       }.inject(template) { |result, token|
         result.gsub(/:#{token.first}/, token.last)
       }.gsub(/\/\//, "/")