Blender Git Loki

* Patch by Raul F Hernandez
This adds a header to the voxel data texture's data file format, to
auto-fill the resolution settings upon loading a file. I don't have a data
file of the right format to test with, so I'll trust it works and wait for
confirmation!

It also adds a 'still frame' setting, to pause the voxel data sequence on a
specified frame, throughout the course of the rendered animation.