Author: Ruslan Kabalin
MDL-30637 Refactor Advanced fileds functionality
The displaying of advanced items has been refactored. The changes are:
* The Advanced button is replaced by the Show Less/More link
* The Show less/more link controls advanced elements only within the section
it is located at
* The Show less/more state of sections is preserved between form submissions
* When javascript is off, all advanced elements will be displayed by default,
no show/hide controls will exists on the page
http://git.moodle.org/gw?p=moodle.git;a=commit;h=ac5e6ca4d1c7f33eb72dcc2953feb02db0657090
http://github.com/moodle/moodle/commit/ac5e6ca4d1c7f33eb72dcc2953feb02db0657090
+ 2.5 en [showless,core_form]
+ 2.5 en [showmore,core_form]