[DGD] Kotaka v0.21, plus first ever upgrade instructions

[Raymond Jennings]

Ok, so I gave this "make things easy to upgrade in place" thing a try and
managed to come up with a few checkpoitns this time to go through before a
full upgrade.

git://git

To upgrade:

1.  Back up your snapshot (always wise)
2.  Check out the tags v0.20.1-up1 and v0.20.1-up2 and follow the
instructions in the commit log for those commits.  Each tag should be read
and followed sequentially
3.  If anything went wrong, poke me

It's kinda rough right now but I'm still green at making things friendly
for a production environment.  Feedback appreciated.