Feature request: allow for custom/theme CKEditor configuration

We should allow for a custom CKEditor configuration (e.g., config.js) in the theme. Could be placed in the /theme/editors/ckeditor folder and a quick check that if exists load it instead of default (which is typically empty of anything but comments.

We could perhaps also allow for custom styles.js file but it can be easily be done via WYSIWYG editor custom configuration by setting it to a url vs the actual styles rules object. http://docs.ckeditor.com/#!/guide/dev_styles