True Types

This is a patch to work around some serious problems in the Sage++
typing system for C and C++ codes. It provides functions for you to
call that "clean up" the SgType's that you get.

I strongly suggest that if you are working in C and not aware of the
intricacies of types, you should call "getTrueType" before doing
anything with a type.

Installation is simple, and the code has already been folded into the
Sage++ master repository. I applied the changes myself to a pure
Sage++-1.3 release and had no trouble.