Unless an explicit fallback is configured. Untested.

- Changed package name to autoradio-server to avoid conflicts;
- fixed systemd service files and defaults;
- added sudo configuration to restart icecast2;
- removed obsolete prerm/postrm scripts.

* Track ModifiedIndex, preventing missed updates
* Properly handle errors in presence protocol

Proxied connections to Icecast are now handled with a simple TCP
proxy that can shutdown each direction independently. Fixes some
connection leaks.