Extracted the shadow-map updating to its own function.
Reformulated the cloud shadows in a more useful form.
Make available a properly smoothed globtime interpolation.
Present globtime as an autoapply uniform and use it for cloudshadows.
Added a new mipmapping mode.
Make floordiv and floormod behavior properly match.
Merge branch 'core' of sh.seatribe.se:/srv/git/client into core