BK-795 Aloha plugin for Search & Replace functionality

I implemented a Google Docs like Find and Replace plugin for Aloha.
I did some changes and added some buttons to the modal window. Also
I've used findAndReplaceDOMText.js plugin to get this task done faster and 
make easier to find text mixed with html tags.

I have overridden some code from older commits and 
squashed them into one single commit (included mine).

If you have any concern, please let me know.