There are 2 kinds of blocks that are undeletable. Those required by the
theme and those protected via the admin page ui. We only want the theme
ones to be auto created site wide if they don't exist - so we need to
rename the theme ones and split the logic.
Now if the current theme requires some blocks that don't exist, they
will be created - but with a new flag that indicates this block should
only be returned if the current theme requires it. This allows flipping back
and forth between boost and clean without restoring the nav and settings blocks
in boost.
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
David Monllao