Merge pull request #15 from csmith/master

Add signing plugin.
Advertise support for self-message. Fixes issue #16
Delete .gitreview

We've ditched gerrit for DMDIrc, so this is now rather pointless.
Merge pull request #21 from ShaneMcC/master

Delete .gitreview
Merge pull request #17 from ShaneMcC/issue-16

Advertise support for self-message. Fixes issue #16
Move git versioning code into a plugin.

Will pull this out into a proper plugin shortly, just wanted
to get it structured right and working.