Updates TinyMCE configuration and adds two more plugins.

New Plugins:

* hr (http://www.tinymce.com/wiki.php/Plugin:hr)
* anchor (http://www.tinymce.com/wiki.php/Plugin:anchor)

Configuration changes:

* Show statusbar
* Set auto resize max height
Adds internal anchor link select to link overlay.

Adds a select box into the internal link tab page of the link overlay.

This select gives the user the option to link to an anchor of current page.

(Also hides the url text field again. It was there only for debugging and has no real value for the user)
Merge pull request #507 from magiclabs/tinymce-config-changes

Tinymce config changes and internal anchor link option.