Fix missing six.builtins

fix #423: pool: LoopExit in imap/imap_unordered

It was possible for IMap/IMapUnordered greenlets to exit without putting the final StopIteration. So, whoever was waiting on the results would have to wait forever (or until LoopExit if there's nothing else running in the program).

Original patch and test by @thinxer (close #424).

Fix #311: same issue.

Fix pep8

Minor fix str/byte issue of subprocess.

Testrunner: do not depend on gevent #38

Fix gevent.socket.socket.shutdown()

Close #384.

initial impl for socket/ssl for python3 #38

py3-related fixes

thanks to @fantix for original patch.

Thanks to @fantix for original patch.

and ignore gevent/util_py2.py

based on #362 by @fantix

Added __bool__ for PY3 next to __nonzero__.

Remove test_support.py

Port gevent vfd to win64

Since long on win64 is 32-bit it cannot hold all possible
SOCKET handle values, making it theoretically possible to
get an exception "OverflowError: Python int too large to
convert to C long" if socket handles become too big. Now
on win64 it properly uses PY_LONG_LONG.

Refs #38, fix pywsgi headers issue in PY3

Ignore sys.exc_clear() for PY3.

Fix indexing exceptions (ex[0]) by using args (ex.args[0]), refs #38