RasterRenderer: Added Documentation to MIX() function
RasterRenderer: Added Documentation to TerrainShading() function
RasterRenderer: Renamed Gmid/Gneighbor variables to center/neighbor
RasterMap: Added Documentation to PixelDistance() method
RasterRenderer: Added documentation to ScanMap() method
RasterRenderer: Moved documentation to the right code part

This comment was apparently corresponding to the integer cast of q
RasterRenderer: Renamed ColorTable() method to PrepareColorTable()

"ColorTable" is a noun, not a verb. Functions/Methods should describe what they
do, not what they are.
RasterRenderer: Improved PrepareColorTable() API documentation
(Weather)TerrainRenderer: Use nullptr instead of NULL
RasterRenderer: Added WATER/WHITE constants and simplified code