Include "chrome-extension" in chrome prefixes.

You can bookmark chrome-extension://... pages.  But you can't use them:
vimium sends you to the default search engine.  This commit fixes the
issue.

Author: smblott-github

lib/utils.coffee

@@ -30,7 +30,7 @@ Utils =
     -> id += 1
 
   hasChromePrefix: (url) ->
-    chromePrefixes = [ 'about', 'view-source' ]
+    chromePrefixes = [ 'about', 'view-source', "chrome-extension" ]
     for prefix in chromePrefixes
       return true if url.startsWith prefix
     false