Add support for Avahi

[Sense Egbert Hofstede]

With the current version of Rapache you can get a domain name by letting the program edit /etc/hosts However, if you want the domain to be used at the whole network you need something differently. Of course you can make the program use a DNS server, but there are a lot of DNS servers in the world and it would be an awful lot of work to support them all.
A different way of letting the world now about your existence is Avahi. You can register a service and Avahi will publish it for you. Because Avahi is an implementation of the Zeroconf protocol it not only works on OSes running Avahi, but on all OS'es running a Zeroconf service discoverer. The service is created by creating a file in XML style telling what the domain name should be and the port. You use the Avahi host file to connect it to the Apache vhost.

Some documentation regarding the Avahi functionality needed:
http://avahi.org/download/avahi.hosts.5.xml
http://avahi.org/download/avahi.service.5.xml
http://avahi.org/download/avahi-publish.1.xml

I once succeeded in creating an Avahi service, but unfortunately I've forgotten how I managed to do it. The documentation isn't very good, it are just some online published man pages. However, the Avahi development team just consists out of four people if I'm right, so that's understandable.

(No .local domains: http://avahi.org/wiki/AvahiAndUnicastDotLocal)