Add Codemirror editor

see http://beta.woltlab.com/index.php/Thread/558-ACE-Editor-im-ACP-einbinden/

Don't know if should provide all the “modes”. Opinions?

![bildschirmfoto vom 2013-06-02 17 55 36](https://f.cloud.github.com/assets/209270/596459/fcb6e056-cb9c-11e2-8858-d72def8c68e6.png)