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.

build_files/cmake/cmake_static_check_splint.py

@@ -58,6 +58,10 @@ CHECKER_ARGS = [
     # re-definitions, rna causes most of these
     "-redef",
     "-syntax",
+    
+    # dummy, witjout this splint complains with:
+    #  /usr/include/bits/confname.h:31:27: *** Internal Bug at cscannerHelp.c:2428: Unexpanded macro not function or constant: int _PC_MAX_CANON 
+    "-D_PC_MAX_CANON=0",
     ]