Ability to execute delimited SQL in DibiConnection::loadFile without SQL errors

For example, if you have trigger in myslqdump’s generated SQL file, it might look similar to this:
```sql
DELIMITER ;;
	/*!50003 CREATE*/ /*!50017 */ /*!50003 TRIGGER `after_insert_table_a`
	AFTER INSERT ON `table_a` FOR EACH ROW
		BEGIN
			UPDATE `table_b` SET
			`column_a` = 0
			WHERE `column_b` = 0 AND `id` = NEW.`table_b_id`; 
		END */;;
DELIMITER ;
```

When loading file with such part, you get some kind of `You have an error in your SQL syntax` exception.

Change in attached commit takes anything between `DELIMITER` statements and executes it at once which works fine ([mentioned in dibi forum](http://forum.dibiphp.com/cs/914-feature-request-loadfile-a-nepovinny-paramater-delimiter)).