Supervoxel example updates

Added better messages to explain single camera transform, fixed bug where negative Z values were always abs'd, even if transform disabled.
Added ability to use normals provided within point cloud, and ability to disable this.
Adjusted visualization so voxels and supervoxels are displayed better.
Cleaned up command line parsing.
I also remembered those files! But you are right, `log(z)` does the right thing for them.