This is a more natural representation than int that allows removal of casts in many places that require uint. Additionally, we can change the internal representation from long to uint, making the Color struct smaller. Since arrays of colors are common, this can save on memory.
* TSVeinsRenderer now shows border cells on the radar
* BuildableTerrainLayer now uses the radar colors defined on the individual tiles
* CliffBackImpassabilityLayer no longer overrides the underlying terrain color.
* Rename LeftColor and RightColor to MinColor and MaxColor
These are mapped from LowRadarColor and HighRadarColor in
the original inis, and appear to be used to set the bounding
values for selecting a random colour, NOT for left/right
pixels (which caused noticeably wrong banding).
* Adjust brightness based on terrain height.
MinHeightColorBrightness and MaxHeightColorBrightness
were chosen by trial/error to match the original
map preview rendering.
