Support for MySQL server running on different port than default 3306

You can now specify the port MySQL daemon is running on. Connections to localhost ignore the port automagically since the connection is getting established via unix sockets. Connections to local MySQL daemons running on ports different from the fefault must be established via host 127.0.0.1.

This would probably close the [old ticket 910555](https://bugs.launchpad.net/chive/+bug/910555) over at launchpad.