[feature/sqlite3] Add support for SQLite 3

Minimum version requirement is 3.6.15 as that's what ships with PHP 5.3.0
when support for SQLite 3 was added.

PHPBB3-9728

phpBB/develop/create_schema_files.php

@@ -70,6 +70,7 @@ foreach ($supported_dbms as $dbms)
 		case 'mysql_41':
 		case 'firebird':
 		case 'sqlite':
+		case 'sqlite3':
 			fwrite($fp, "# DO NOT EDIT THIS FILE, IT IS GENERATED\n");
 			fwrite($fp, "#\n");
 			fwrite($fp, "# To change the contents of this file, edit\n");