SevenSky - physically based sky rendering library

[Ali_RS]

@The_Leo

I wanted to do this, but then I put it off for later, sorry. There’s little bit of work to do: add moon/planets to test case, rewrite Stars to use instancing, and add ambient skylight (eg. when there is neither sun nor moon in sky). Well, eventually I’ll get it done. They’re not big tasks, just got to get back to this. i’ll try to get it done by this week.

Thanks.

Regarding PBR issue, I am also using JME3 PBR. I have not tested it with SevenSky yet, It would be nice if it works seamlessly with JME3 lightprobe so.