Fix Problem with text selection ending outside the container div
https://github.com/daviferreira/medium-editor/issues/88
Merge branch 'master' of https://github.com/daviferreira/medium-editor

Conflicts:
	dist/js/medium-editor.js
	dist/js/medium-editor.min.js
	src/js/medium-editor.js
Add Stringify Demo
``` stringify([space]); ```

### Summary: ###

Return converted editors content to JSON.

### Parameters ###

**space**

Causes the resulting string to be pretty-printed.
The space argument may be used to control spacing in the final string. If it is a number, successive levels in the stringification will each be indented by this many space characters (up to 10). If it is a string, successive levels will indented by this string (or the first ten characters of it).
Fix JSlint warning: Convert variable double quotes in single quote.
Merge with git@github.com:devalnor/medium-editor.git
Transforms stringify into serialize, removes demo, adds spec
Updates dist JS
Merge with serialize feature branch