Change rules for LOD voxel rounding so min and max are not rounded separately
- Change rules for LOD voxel rounding so min and max are not rounded separately (i.e. all voxels covering the requested area) but instead gets a consistent number of voxels independent of how the min is rounded.
- Update VolumeDataRegion code to match commercial VDS including logic to skip duplicated voxels in LOD chunks.