Cmake small updates to match Makefile

Previously we were compiling against the system headers, and then
linking against a different libstdc++.  Fixes #252.

Also, move the gtest install section into the "required dependencies"
section since you need it to pass "make check".

Trying to fix Issue #171

fix bug #171: a first attempt

There are two tricky things left that I don't think we can support soon:
- MultipartConversionError uses multiple inheritance
- structseq.c sets a tp_dealloc

The structseq_dealloc function is a "simple" destructer (functionality is
covered by our GC), so we can just comment it out.  Ideally we'd have some
way of automatically determining that it's a no-op so that we don't have
to run it.

Ie run lint.py tester.py under Pyston, and use Pyston on the setup.py
script to build our test extension modules.

Pass SELF_HOST=1 to make to invoke this behavior

Looks like for now this only changes double-closing-angle-brackets
(now formats "> >" as ">>" in templates), but apparently it has
effects on raw string literals as well.

Starting to really hit critical mass in terms of having enough
API support that it's easier to copy additional API functions over.

And turn off that part of the fork.py test as well

My first stab at writing CMake rules

Required a small amount of object changes, and then a large
number of replacements where we directly compared the class
to int_cls.  We now check that it's a subclass, since you
are allowed to use True/False anywhere that you could use
an int.  ex "xrange(0, n, step=True)"