Lighting and LoS

[LPGhatguy]

There's a rough prototype of this committed right now.

A simple approach is to keep the initial color of every part in a map when we instantiate a map tile. To darken the tile, we can convert the color to HSV or HSL, tweak the value or lightness multiplicatively, and then apply the color to the part. We can fade actors and objects standing in darkness or out of line-of-sight.

I'm not sure what kind of lighting settings we should use in Roblox itself. Ideally, pitch black parts should be very dark, but I don't want to lose bright stuff in the process.