[ticket/11015] Make DBAL classes autoloadable

PHPBB3-11015

This allows us to just create the object without having to include the
driver first. However, it also means that users must specify the full
class name in config.php

tests/test_framework/phpbb_test_case_helpers.php

@@ -54,7 +54,7 @@ class phpbb_test_case_helpers
 		if (extension_loaded('sqlite') && version_compare(PHPUnit_Runner_Version::id(), '3.4.15', '>='))
 		{
 			$config = array_merge($config, array(
-				'dbms'		=> 'sqlite',
+				'dbms'		=> 'phpbb_db_driver_sqlite',
 				'dbhost'	=> dirname(__FILE__) . '/../phpbb_unit_tests.sqlite2', // filename
 				'dbport'	=> '',
 				'dbname'	=> '',