at last

I worked on slave DNS support in the dev-dns branch tonight. I had trouble with the service stuff, but I got over it and I can happily announced that we crossed a significant milestone in DNS support:

We now have basic DNS support in Aegir!

There is still a ton of work to do, but it is the bare minimum for a basic setup:

• Creating a site creates a "A" record (and a zone, if necessary)
• Deleting a site deletes that record (and that zone, if empty)
• Zone creation and deletion are configured on slave servers
• Basic commandline utilities exist to manipulate the zonefiles
• Manual edits to zonefiles are not kept