Revert "remove shade range check from shader"

This reverts commit 7f5100d.

I can't find any problems caused by the change but removing the change from the
"Standart" routine does cause problems so I can't really assume that shades
will be within the alloewed range apparently.

Author: hmaon

src/Engine/Surface.cpp

@@ -704,12 +704,10 @@ struct ColorReplace
 		if(src)
 		{
 			const int newShade = (src&15) + shade;
-#if 0
 			if (newShade > 15)
 				// so dark it would flip over to another color - make it black instead
 				dest = 15;
 			else
-#endif
 				dest = newColor | newShade;
 		}
 	}