and with the fixes to get that working, all the tests pass!

Add a PYSTON_NOEXCEPT define that gets defined to "noexcept" in C++ mode,
and to the empty string in C mode.

I don't think 'extern "C"' implies noexcept.

This is partly for better performance when we know that a function cannot throw
an exception, but also as an annotation for us since the exception model is
the main difference between C land and Pyston land.

Vim substitution: %s/\(\<PyAPI_FUNC\>(.*).*(\([^)]\|\n\)*)\);/\1 PYSTON_NOEXCEPT;/gc
- This will catch almost all cases, except for functions not marked with PyAPI_FUNC
  and function definitions that have extra paretheses (in comments, usually)

Most involved was the recursion checking stuff: switch to
providing the C API thread state rather than our internal
one, since they are mostly the same.

The recursion checking code doesn't mean much while most stuff
doesn't use it, but hey at least it's supported now.

Our previous directory names:
include/
lib_python/2.7/
lib_python/2.7_Modules/
lib_python/2.7_Objects/
lib_python/2.7_Python/

new directory names:
from_cpython/Include/
from_cpython/Lib/
from_cpython/Modules/
from_cpython/Objects/
from_cpython/Python/

Sorry for the huge diff, but I think this makes way more sense.

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

Remove some definitions that should no longer be in there
(structs for which we have Pyston-internal definitions).

Instead of doing "typedef void PyIntObject", do
"struct _PyIntObject; typedef struct _PyIntObject PyIntObject;"
which prevents spurious things like type conversions or
sizeof(void)'s.