Error message: When MySQL driver is not installed

I just ran into this issue: `Error - Undefined constant Gt\Database\Connection\Connection::MYSQL_ATTR_INIT_COMMAND /home/g105b/Code/PhpGt/Database/src/Connection/Driver.php:49`

It seems such an obscure error, but really it should say "Your PHP install does not have PDO's MySQL module installed". This should be detectable during the constructor.