socket: add wait_read/wait_write/wait_readwrite to __all__: it's a useful API that should be public and stable

setup.py: remove code related to guessing libevent version; do not set USE_LIBEVENT_? macro, it's no longer used

-1 and -2 options are gone

- that way __del__ on local is not necessary

monkey: make patch_thread() use gevent.local.local; also make it explicitly set threading.local and _threading_local.local

coros: reimplement Semaphore similarly to how Event is implemented; add rawlink() and wait() methods

- add DummySemaphore class

http://code.google.com/p/gevent/issues/detail?id=24

- it's no longer used by gevent itself