Previous attempts at vmbuilder-debian

Eric Hammond informed me of a previously-existing branch of vmbuilder which was adding Debian support. It currently has only etch support, but I decided to work off that.

I've merged it into the existing Git which is currently based off the Vmbuilder trunk. There's not much difference between the two anyway: the trunk has packaging that the branch doesn't, and the branch has a Debian plugin and frontend which the trunk doesn't.

Now to set it up and see if it works.