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

MDL-17327 database : fixed comparisions in sql to be cross db compatible in data_get_advanced_search_sql()

This was failing under the MSSQL database drivers.

Thanks Dan!

Merge branch 'master_MDL-31908_glossary_entrylist_print_version_not_showing_content' of git://github.com/kanikagoyal/moodle