Merging release branch 1.4.2 into develop

* release-1.4.2:
  [FIX] Magento connect ...
[FEATURE] Add CodeMirror editor
[FEATURE] Add EpicEdit 0.22 beta, removed marked.js because included in EpicEdit
[FEATURE] Update EpicEdit 0.2.2 beta, config option in the backend for epic editor config.
Remove old preview, add load/unload Epic Editor for inserting custom Magento variables.
[FEATURE] Update EpicEdit 0.2.3. Proper loading of editor in tabs sections
[FEATURE] Implementation EpicEdit, renaming, bug fixing ...
[FEATURE] Configurable cheat sheet url per store view
[FEATURE] remove of markdown detection tag before switching into preview
[FEATURE] loading epic editor in catalog category edit -> https://twitter.com/iamdevloper/status/378464078895017984 :-(
[FEATURE] loading and unloading epic editor in every form / wysiwyg editor
[FEATURE] loading and unloading epic editor in every form / wysiwyg editor; bug fixes
[FEATURE] add css class system_email_template_edit and add event markdown_adminhtml_epiceditor_inject to modify the css class array for custom implementations
[FEATURE] fix markdown epic editor in transactional email templates
[FEATURE] add promise library https://raw.github.com/stackp/promisejs/master/promise.js
[FEATURE] parse markdown via ajax with php lib markdown extra. implemented promise
[FEATURE] parse markdown via ajax with php lib markdown extra. implemented promise
[FIX] rendering of markdown extra in transaction email. Preview render url for md extra. Update readme
[FEATURE] view html source
[FEATURE] view html source: add highlight.js
[FEATURE] view html source:  highlight.js implemented