KappaPT Preview P9

Oi, 

time for some updates on this pack, although I am currently not really touching the PT lighting part but rather keeping everything around it up to date for the time being.

- updated tonemap implementation and behavior (now up to speed with the latest Kappa 4.1 changes)
- tweaked skylight
- minor cloud improvements
- added support for cloud shadows
- improved POM shadows
- changed labPBR metal albedo application

As always, I hope you enjoy this update :)