Added method to return indexed array for Connection

Code speaks for itself..
Did not find a test for fetchAll() in ConnectionTest.php so didn't make a test for this function either. Works though.
Function name is up for debate. Possibly needs to be refactored so that fetchAll() accepts PDO fetch style types as described here:
http://www.php.net/manual/en/pdostatement.fetch.php
and
http://php.net/manual/en/pdostatement.fetchall.php