Removed chat

Removed chat according to:
https://github.com/rosedu/wouso/wiki/Plan-24.02.2014

The following chat related issues can also be closed:
https://github.com/rosedu/wouso/issues/239
https://github.com/rosedu/wouso/issues/238
https://github.com/rosedu/wouso/issues/237
https://github.com/rosedu/wouso/issues/171