* PBO single layer copy, part 1
Still needs ability to take and set width/height slices. (using pack paramaters)
* PBO Copies pt 2
* Some fixes and cleanup.
* Misc Cleanup
* Move handle into the TextureInfo interface.
This interface is shared between texture storages and views.
* Move unscaled copy to the TextureCopy class.
* Address feedback.
cf7044e37b