At the same time this commit introduces a standardised dialogue YUI module to enrol and implements it across the board.
This commit also addresses MDL-23292 and MDL-23319.
* Set the default per page limit to 100 instead of 20
* Set the default enrolment role to enrol_manual:roleid config
* Added course name to page title
* Fixed centering bug of cohort dialogue
* Fixed double display bug