Scene Graph or Manager

[fesoliveira014]

I don't know if this is strictly necessary since we are dealing with voxels, but a scene manager might be a good idea, specially when we want to draw a lot of stuff on the screen. The chunk manager in itself is a kind of scene manager, but it can only help managing chunks of voxels, which won't always (most of the time) be the case. This is not necessary for other systems to work well, but might be a good addition.