Renamed gem from "wysihtml5x-rails" to "wysihtml-rails" and released version 0.5.0.beta2.

* Added latest version of wysihtml (previously wysihtml5x)
* Bumped version to 0.5.0.beta2
* Moved gem repository from https://github.com/Edicy/wysihtml-rails to https://github.com/Voog/wysihtml-rails due rebranding of the wysihtml and Edicy (now Voog - www.voog.com).