Switch to reading from `binvoxel` files instead of `obj` files

[khasmamad99]

obj files have to be read into a mesh object which is later converted a voxel grid. Instead directly reading a voxel grid from binvoxel files will increase efficiency.

[khasmamad99]

Looks like binvox files store voxels of dimensionality 128x128x128. I will have to figure out decreasing the dimensionality to 32x32x32 to be able to use them.