Fix deprecation warnings

_config.yml

@@ -3,8 +3,7 @@
 #permalink: /:categories/:year/:month/:day/:title 
 
 exclude: [".rvmrc", ".rbenv-version", "README.md", "Rakefile", "changelog.md"]
-auto: true
-pygments: true
+highlighter: pygments
 
 # Themes are encouraged to use these universal variables 
 # so be sure to set them if your theme uses them.

atom.xml

@@ -1,5 +1,5 @@
 ---
-layout: nil
+layout: null
 title : Atom Feed
 ---
 <?xml version="1.0" encoding="utf-8"?>
@@ -25,4 +25,4 @@ title : Atom Feed
  </entry>
  {% endfor %}
  
-</feed>
+</feed>