Prevent Connection from maintaining a second reference to an injected PDO object. Previously, if a developer explicitly closed the Connection, only the _conn reference was destroyed, but the _params['pdo'] reference remained and kept the PDO connection alive. By unsetting the _params reference, we maintain only the _conn reference, exactly as if the PDO connection is generated internally.

References:
SQLA16 - http://dcx.sybase.com/index.html#sa160/en/dbadmin/serverport-network-conparm.html
SQLA12 - http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.sqlanywhere.11.0.1/dbadmin_en11/serverport-network-conparm.html

Fixes the warning emitted by mysqli when sqlstate is not set (yet?).
http://git.php.net/?p=php-src.git;a=blob;f=ext/mysqli/mysqli_prop.c;h=2d36336372b75922bd8fbf40c5c9054a5230c8a0;hb=HEAD#l36

Warning masks actual connection error.

Adding doctrine-dbal to composer.json and making it work just like doctrine command (from Doctrine ORM)