Hightmap and Hillshader improvements
Heightmap now renders as single channel grayscale PNG/TIFF (8, 16, 32 bit) Fixed pixel clipping in Hillshader, added ray marching and long shadows
Heightmap now renders as single channel grayscale PNG/TIFF (8, 16, 32 bit) Fixed pixel clipping in Hillshader, added ray marching and long shadows