Make it actually work. Also some changes:
- removed support for helper protocols. They don't belong to ioslave - maybe plasma applet
- use hardcoded protocols. Configurability is good but let's not go overboard.
- added fish:// support
- temporarily removed support for multiple domains (default domain is always used) - kdirmodel does not like listing zeroconf://domain/_ftp._tcp/name from inside zeroconf:/_ftp._tcp/