* Added additional instructor capability for managing Course Categories
* Added unit elements preloader
* Course completion actions added for developers: 'coursepress_student_course_completed', 'coursepress_student_course_unit_completed'
* Unit completion actions added for developers: 'coursepress_student_course_unit_pages_viewed', 'coursepress_student_course_unit_mandatory_question_answered', 'coursepress_student_course_unit_gradable_question_passed'
* New options for "Who can enroll" when not allowing anyone to register to your site.
* Fixed WordPress 4.1 issues (hidden course list in the admin, hidden assessment list)
* Fixed "administrator" role for network sites.
  CoursePress menus and permissions now work properly for new sites.
  For old sites the administrator's role will have to be reset (change to "subscriber" then back to "administrator").
* Fixed shortcode typos on the settings page
* Fixed issue with prerequisite courses for non-logged-in users
* Fixed issues with enrollment/signup button
* Fixes issue with unit editors upon reordering elements (Firefox)
* Strip html tags from the assessment comment ALT and TITLE
* Fixed issues with dummy course not being created upon first install 
* Other code improvements

git-svn-id: https://plugins.svn.wordpress.org/coursepress/trunk@1050565 b8457f37-d9ea-0310-8a92-e5e31aec5664