MDL-37009 Created functions in core_course_renderer to display courses and categories listings
MDL-37009 Display single course info box using new course listings renderer

Header is removed from /course/info.php because it is now part of renderer function
MDL-37009 Added function core_course_renderer::courses_list() similar to print_courses()
new course listings on frontpage
added function core_course_renderer::courses_list_frontpage() - not exactly correct
MDL-37009 Display courses and categories tree on /course/index.php using new renderer

Also /course/category.php
MDL-38304 moved editing functionality from course/search.php to course/manage.php
course/search.php
added function core_course_renderer::search_courses() - has TODO
MDL-37009 Display list of tagged courses using new renderer
MDL-37009 new course listings: changes to base, standard and afterburner themes
MDL-37009 new course listings: changes to canvas and other themes:

canvas-based themes: formal_white, magazine, splash
some minor changes to print_course_request_buttons() - don't know why
--- accidental commit
EXPERIMENTAL: add 'can-access-course' class to accessible courses