Fixed bug#9374 - Add more functions to rich text editor.

Squashed commit of the following:

commit 4922d243205355d20cf6a92e5bfb6252db98ebb5
Author: Marc Nilius <marc.nilius@otrs.com>
Date:   Tue Apr 30 14:24:51 2013 +0200

    Removed possibilty to resize horizontically.

commit a546a82ca68f05002450f22ccffeefa1c65e239d
Author: Marc Nilius <marc.nilius@otrs.com>
Date:   Tue Apr 30 14:24:25 2013 +0200

    Reverted changes for resize event.

commit 31d3b72c9663301014621a85727c14d1538053a7
Author: Marc Nilius <marc.nilius@otrs.com>
Date:   Tue Apr 30 13:03:52 2013 +0200

    Added CKEDITOR js event to handle horizontal scrolling.

commit ebcfdbe55fe569411a87cfe817c6a7a9a644a7b3
Author: Marc Nilius <marc.nilius@otrs.com>
Date:   Tue Apr 30 11:45:14 2013 +0200

    Added new options/icons to CKEDitor.