Attempt to improve voxelizer

[wrapperup]

In addition to the other PR, I made few small changes to the voxelizer. I wasn't sure if this was intended behavior, so I made a new PR for these changes. A new method of determining if a voxel is inside the mesh is used (using the face normals), here are the results:

Test scene (Voxel detail of 26):

Current (Voxel detail of 26):

New (Voxel detail of 26):

Test diamond (Voxel detail of 32):

New result (Voxel detail of 32):

Let me know what you think!

[eyemine]

I love it but, I'm not very technical and while I am quite adept in Magicavoxels, but I only have basic skills in Blender so far, so I struggle with the .vox addon. Sometimes I can get it to work and other times I get a portion of the model or I just get empty 1k files. I was using the Spyduck version before, but I have now installed your version. I wish I knew what I was doing wrong, I guess when I know my way around Blender better it will become obvious.. How can I preview like you have shown above please?