instance is has been used instead of cmid. This works as all id's are 1
in most cases, but not always.
accesslib_clear_all_caches_for_unit_testing was updated to clear the
$USER->access cache which would fail test when the wrong user's data was used.
Most srand instances are removed to allow PHP to do the work.
srand was left for group randomization due to the method used.
Conflicts:
lib/tests/accesslib_test.php
Includes:
* constants refactoring
* reworked db table init
* support for $CFG->debug = -1
* functional DB tests
* fixed $DB->get_indexes() to not throw exceptions when table does not exist
* fix handling of user passwords in test db
* add debug info to exception messages
* removed unnecessary PHP debug errors from mathslib
* fixed @error suppression in get_string
* fixed PHPUnit error handler setup
* added timezone info to default install
Russell Smith