PHP5 used to update error_reporting to 0 on functions called with the
suppress errors operator (@). In PHP7 it is not updated.
Credit to Rajesh Taneja.
The simplepie tests time out too quickly due to a low connect timeout,
to fix this:
* Introduced a way to set the timeout during intitial construction
* Converted the unit tests to use a high timeout value
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
