Add to Hackage

[meteficha]

It would be nice if you added your package to Hackage. Don't worry if you feel that it's still too immature: Hackage is a mother that loves both her old and young offsprings 👍.

[blitzcode]

Done! (http://hackage.haskell.org/package/hackage-diff)

hackage-diff certainly hasn't been widely tested, but it's 'stable' enough because it pretty much does everything I wanted it to do. I'd expect it to stay like this on Hackage unless major bugs are discovered or I need to fix the build for a new GHC.

[meteficha]

Thanks! :)