Window/Skylight Interior Shading Fraction

[shorowit]

For windows/skylights, splits InteriorShadingFraction into InteriorShadingFractionSummer and InteriorShadingFractionWinter. Many software tools and standards use two different numbers.

[nmerket]

Seems fine to me. I do have questions about when each factor applies. Should we be providing a way to better specify that?

[lirainer]

@nmerket Excuse my git-ignorance, but seems we should note that all these changes have been superseded by #202?

[shorowit]

@lirainer What do you mean? The change is preserved in #202, aside from being renamed to SummerShadingCoefficient and WinterShadingCoefficient:

[lirainer]

I guess what I'm trying to say is that the changes made in this PR never show up in 3.0 (especially if all the commits are squashed?) It was confusing to me to see the ShadingFraction elements show up here when we ended up using ShadingCoefficient.