Fix lwjgl library and remove unnecessary source.

You don't need source code for the external libraries. You just need the jars and the natives. Also, the lwjgl version you include with your files was broken for me, and so I've fixed that.

You should use the libraries that you include with your package when you test it. That way you know that they actually work.

Sorry this commit is so huge. It's mostly because your first commit was so huge, and I had to undo a vast majority of it.