OsTerrainSetHeight
From OpenSimulator
LSL: integer osTerrainSetHeight(integer x, integer y, float val)
C#: integer osTerrainSetHeight(integer x, integer y, double val)
Sets terrain height X & Y Values, double = float.
osTerrainFlush should be called after all the terrain-changes have been done to update Terrain Data.
NOTE: INCOMPLETE, needs further data to complete with example.
