Rich text box

Added a rich text box component.
Right now using [nicEdit](http://nicedit.com/)
I chose that library because it is light weight and easy to integrate
Still have issues with styling, ie: width is hardcoded and doesn't pickup changes, but still very nice in general

![image](https://cloud.githubusercontent.com/assets/4157103/5221595/95ca76b2-764c-11e4-82d3-c0e367d5c5e3.png)
I think this file should go in `mykoop-core/vendor/nicEdit`.