changes for materials to treat them as shorts not int/chars (since they are stored as shorts intermally)

- converting nurbs to mesh was casting the material to unsigned char.
- subsurf was casting to char, then int -> short in a loop.
- have material functions take & return shorts.

source/blender/editors/mesh/meshtools.c

@@ -217,7 +217,7 @@ int join_mesh_exec(bContext *C, wmOperator *op)
 			
 			if(me->totvert) {
 				/* Add this object's materials to the base one's if they don't exist already (but only if limits not exceeded yet) */
-				if(totcol < MAXMAT-1) {
+				if(totcol < MAXMAT) {
 					for(a=1; a<=base->object->totcol; a++) {
 						ma= give_current_material(base->object, a);
 
@@ -231,7 +231,7 @@ int join_mesh_exec(bContext *C, wmOperator *op)
 							}
 							totcol++;
 						}
-						if(totcol>=MAXMAT-1) 
+						if(totcol >= MAXMAT)
 							break;
 					}
 				}