* When a label is passed to an (advanced) checkbox and no text
was provided, the label will be displayed on the right of the the
checkbox element. So there's no point in passing an empty string for
the label just to render the text to the right of the checkbox.
* Coding style clean up.
* SQL indentation
* Removal of non-matching capabilities when searching.
* Fixed notices/warnings when hitting enter on search.
* Can now compare multiple capabilities at the same time.
* Capability search now persists between requests.
* Upgraded to use renderers.
* Upgraded module.js to YUI shifted module.
* Converted deprecated calls.
* Converted forms to Moodleforms.
* Implemented backend functionality to overview at
different context levels. Not possible presently as
there are no front end hooks.
Ilya Tregubov