Changed convert to add '0' or '0x' prefix for oct/hex. Added NULL function pointers for shift and mask ops.
Changed convert to add '0' or '0x' prefix for oct/hex.
Added NULL function pointers for shift and mask ops.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator