cache: implemented a course cache and supporting API
cache: converted grade scripts to use course cache
cache: converted report, notes, user, and calendar scripts to use course cache
cache: converted admin, backup, blocks, repository, rss, and tag scripts to use course cache
cache: converted course scripts to use course cache
cache: converted lib scripts to use course cache
cache: converted enrol scripts to use course cache
cache: converted mod_forum, mod_data, and mod_glossary scripts to use course cache
cache: fixed bug in courselib.php prevent modinfo from being loaded
cache: fixed several bugs with current approach