Major refactory of the code. Refactored functions to register content blocks, content blocks templates, some tweaks at tinyMCE instance (requires WP 3.9 alpha with tinyMCE 4.0), moved plugin from prototype page to add new / update posts page. Initial planning for save the post content data as a JSON collection.

git-svn-id: https://plugins.svn.wordpress.org/wp-content-blocks/trunk@850912 b8457f37-d9ea-0310-8a92-e5e31aec5664