Running Mopidy as a daemon in Debian

Hi y'all,

I forked the "debian" branch and added a small Debian package for running Mopidy as a system daemon.

The additional package is named "mopidy-daemon", depends on the "mopidy" package (so I could use the current version from the repo), and provides:

- a system user "mopidy" in group "audio" with home /var/lib/mopidy
- directories /var/cache/mopidy, /var/lib/mopidy/media, /var/lib/mopidy/playlists, /var/lib/mopidy/log
- an init script /etc/init.d/mopidy-daemon
- default configuration for init script in /etc/default/mopidy-daemon
- minimum default configuration in /etc/mopidy/mopidy.conf, with setup for local music/playlists in /var/lib/mopidy/{media,playlists}
- separate logging configuration in /etc/mopidy/logging.conf, with log output directed to /var/log/mopidy/mopidy.log
- running "/etc/init.d/mopidy-daemon force-reload" invokes mopidy-scan
- except for adding the new package to debian/control, no interference with existing code

I'd greatly appreciate if you gave this a look, and let me know what you think of it.  I've tested on Ubuntu 13.10 and Raspbian.  My primary goal for this was to replace MPD on my Raspberry Pi "kitchen radio"; looks good, so far ;-)

Kind Regards,
Thomas