Orange: New option "Shadow Bias", to extend the boundary between shadow or

no shadow a little bit. Uses same threshold function as the "Bias" button.
(That latter still works, and will use an automatic bias value based on the
geometry, to prevent terminator errors in raytracing).

Anyhoo, with this manual bias you can get rid of terminator problems for
weird diffuse shaders now as well (like tangent or fresnel).

Committed a few more files than needed, that's just code cleanup.

source/blender/blenloader/intern/readfile.c

@@ -3198,7 +3198,6 @@ static void lib_link_group(FileData *fd, Main *main)
 			}
 			if(add_us) group->id.us++;
 			rem_from_group(group, NULL);	/* removes NULL entries */
-			
 		}
 		group= group->id.next;
 	}