Sbt integration

I integrated SBT with your project (not so many scala game engine unfortunately, and i like your code). I already tried it two months ago but there were some problems with the old cokeandcode repository. Now it's okay.

I have to test some more things because i'm using one SBT plugin called "SBT LWJGL plugin" (https://github.com/philcali/sbt-lwjgl-plugin) which is pulling automagically LWJGL/Slick2D (are you still using Slick2D ?) dependencies. The problem is the revision of this pulled LWJGL is 2.7.1. It seems to work but it's probably not the best deal. Anyway, better than nothing.

Just run "sbt test" if you wanna try :). Hope you'll enjoy it.