Add inTransaction() to ConnectionInterface

[Koopzington]

Since the Interface already has beginTransaction() and commit(), i'd suggest adding inTransaction() to the Interface. The property is set by the classes themselves in these both methods so I don't see why inTransaction() shouldn't be added to the interface. ConnectionInterface.php

AbstractConnection.php IbmDb2/Connection.php Mysqli/Connection.php Oci8/Connection.php Pdo/Connection.php Pgsql/Connection.php Sqlsrv/Connection.php