Add a hodgepodge of CAPI support features
Create a new directory for things that came from CPython's Python/

Should probably reorganize/rename the "lib_python" directory at some point.
Move from our custom getargs.cpp to CPythons getargs.c
Switch from our custom posix.cpp to the CPython posixmodule.c

I thought we weren't going to be able to do it since posixmodule.c
is 9kloc, but it's working!

Had to make one modification to posixmodule.c where it was directly
accessing the fd of a file object; haven't figured out the best way
to handle this.
Merge branch 'capi'
[wip] remove _abcoll