[Compiler-sig] Update to compiler for Python 2.0

[Jeremy Hylton]

I ended up taking a brute force approach to this problem: I
implemented the missing bits for 2.0 and then added backwards
compatibilty support for 1.5.2.  I tested this using the new regrtest
script, which compiles and runs the entire test suite to make sure
that the compiler works.

I hope this doesn't interfere with any of the .NET stuff you are
doing.  If there are any problems, I'll try to fix them.

Jeremy