use interface to be compatible

[dirkwinkhaus]

provided connection class PrimaryReadReplicaConnection is no child from \Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connection. this causes issues when doing this:

$entityManager->getConnection()->prepare($sql)

therefore the implementation of the ConnectionInterface is neccessarly needed to call "prepare" on PrimaryReadReplicaConnection.

[dirkwinkhaus]

Hey there,

when i was using the \Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connections\PrimaryReadReplicaConnection and tried to do this:

$entityManager->getConnection()->prepare($sql);

it created an error because the connection of type \Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connections\PrimaryReadReplicaConnection inherits Doctrine\DBAL\Connections\PrimaryReadReplicaConnection and is no member of \Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connection which has to be for 2nd argument of \Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Statement. Using the \Facile\DoctrineMySQLComeBack\Doctrine\DBAL\ConnectionInterface as type hint in statement will solve this.

[thomasvargiu]

I'm going to merge this as an hotfix, then we're going to refactor some code for consitency.