WIP: .obj loader including .mtl and tetxure loading.

• A Very crude implementation of a .obj loader
• The .obj loader integrates with the existing model, material and textures systems.
• To test it, run this scene.

./cube assets/scenes/objview.yml 

• Remember to check that config.yml contains the ObjFolder: assets/objs
• .obj models and materials will hot-load together with the existing models and materials.
• All .obj models use the objshader.glsl
• Obj model folders that are dropped into the assets/objs will be automatically loaded and available during run-time.
• Example: objs/cube/cube.obj, objs/house/house.obj.
• It is important that the folder and the .obj file has the same name.
• Obj models can be accessed in the scene files by their model name like so

entity: skybox
    model: obj/house
    position: 0 0 0
    rotation: 0 0 0
    scale: 1 1 1
    velocity: 0 0 0
    angleVelocity: 0 0 0