Phone ringing/dialing and echo cancelation.

The phone ringing and dialing sounds are configurable in the sounds menu. The parameters for webrtcdsp are not configurable yet, although I plan to add this in the future.

Reminder: If you guys are happy with the echo cancelation you can update this

Notice: the phone ringing implementation is not ideal atm. It needs to be reworked, probably with another sound api for linux because the gsound api is trash. I did not want to introduce new dependancies so I hacked together what I could with gsound. I guess I should make an issue about this on the tracker.

If my patches are not satisfactory in any way I am ofcourse happy to rework in any way nescessary.

Greetings, Emil