Add Sparkle updating

[soffes]

It would be great if Missing Drawer could update itself. This should probably be off by default though.

[jezdez]

Totally. I think there is a fork that implements that. I suppose that would also require us to start using some kind of saner version scheme, e.g. http://semver.org

[soffes]

Ya if you noticed I recently added a version. (I should read http://semver.org though.) We could have the file Sparkle hits in the GitHub downloads so there wouldn't be a need for a server.

I'll take a look through the forks.

[jezdez]

Wow, awesome, didn''t see the change. Yeah, 0.4.0 makes sense.