Fix upstart config

This PR prevents `start avahi-aliases` from hanging and tracks the appropriate PID.
Bugfix: this crashes the daemon

h/t @rwos
Bugfix: correct documentation
Merge remote-tracking branch 'xdissent/patch-1' into topics/make-it-run
Enhancement: simplify path creation

I think this makes more sense, since `/etc/avahi` is not available on
Windows anyway. So no need to be obscure^W^portable.
Merge branch 'topics/make-it-run' of ssh://github.com/till/avahi-aliases