Removed PBCK Code Editor

Why? These are the following reasons:
 - It magically disables bold / italic buttons (possibly the most
   important buttons for the editor)
 - Inserts code but it is not really useful for end-users
 - A toggle will be made to switch to Ace Editor for programmers, this
   will be not useful for programmers

Also, I added a small section of config code for autogrow plugin. It
makes it more usable.