Use postMessage to communicate between the iframe and TinyMCE.

This gets around cross-origin issues on the CDN.

Delete plugin.min.js as the Jake command will minimize into the full file.
Tiny MCE version 4.0.20

Changed tiny-MCE to not load CSS files dynamically.
Added CSS files for tiny-MCE in env files.
Moved TinyMCE files to directory structure required by Jake command.
Changed clients of "tinymce.min.js" to use "tinymce.full.min.js" instead.
Updated CHANGELOG to indicate tinymce version 4.0.20.
Renamed tinymce.css.
Directions for creating tinymce.full.min.js and commenting of edX changes.
Updated comments related to disabling dynamic JS and CSS file loading in tinymce.
Allow TinyMCE to handle CSS within the iframe.
removing tinymce button border only on active to counteract fun LMS button styles
Add dialog plugin code to compressed JS file and CSS file.

Needed for TinyMCE CodeMirror plugin.
Directions for creating codemirror-compressed.js
scoping TinyMCE editing CSS to just tinyMCE context-based elements
revising default (minified) TinyMCE content CSS to be scoped to .mce-content-body element
Update default font size to 14 for bulk e-mail editor (LMS).
Studio: syncing up font-based styling between TinyMCE editing view and Studio HTML xmodule preview

Separating and documenting tinyMCE font imports from customized vendor code and customized render styling css files (because font must load first in iframe).

Add the TinyMCE font file to the CMS pipeline.
Match our default code editor font size of 13.