Milestone Avahi 0.6.6

This release fixes some bugs and includes some documentation updates

• Add a bunch of new types to the service type database
• Return errors of avahi_entry_group_commit() properly
• Many doxygen documentation improvements
• Fix destruction of AvahiEntryGroup? objects using avahi_entry_group_free().
• Don't allow commiting of empty entry groups
• Use a little less memory in avahi-qt
• Don't accept empty TXT strings
• Update example "client-publish-service.c" to show how to modify an existing service

This release is backwards compatible with Avahi 0.6, 0.6.1, 0.6.2, 0.6.3, 0.6.4 and 0.6.5