Merging fonera client and listener (now works)

When I first wrote the fonera interface, I thought that there were two connections established, one per direction. I was wrong. This PR removes the Fonera proxy and enhances the Fonera server so that message/sound etc. commands can be sent from there.

The fonera server will accept only one connection and close the previous one when a new one arrives.

Additionally, the relevant config options have been renamed to a saner default (`control_local_*` and `control_remote_*`).

This is still a WIP, wait before merging.