added Wavefront .OBJ parser in Renderer.Mesh.OBJ

I in the process of learning haskell, but I saw this project and looked through the code. It seemed *fairly* simple, but I saw a lot of things to learn :). I added this OBJ parser based on one I had written in Go for my own project. I had more to add to the parser, but as I read through how it was being used, I just left it at parsing vertices.

Feel free to criticize and change my work, because I'm still learning. For instance, I know the "case of -> case of ->" stack of code could be condensed, but I didn't figure it out.