Add Rich Text Editor 

Replaces NB's <code>textarea</code> with a Rich Text Editor, using the CKEDITOR library. Functionality includes Math Formula Formatting and Code Syntax Highlighting. 
The regex I used strips all the html tags so that the comment does not get styled in the notepane. Also, I am not sure why, but even though I am not calling the substring method on htmlStrippedString, it still only displays a snippet of the comment.