returning `Connection`

[filchristou]

Currently remote_repl returns a connection and writes to the global _repl_client_connection.

And connect_repl doesn't return a connection but also writes to the global _repl_client_connection.

I find this behavior inconsistent. Is it necessary that connect_repl returns the ReplMaker prompt ?
In any case, I think it would be nice to also return the Connection.
This way the client can always have a way of closing the connection. (without having to access the global _repl_client_connection)
Aside from that, this could also enable handling multiple connections.