temporarily disable EV_CHILD since it breaks Python's subprocess and os.waitpid because of child reaping

also make sleep(negative) equivalent to sleep(0); raising an error really has no use here;

- it now avoids unnecessary blocking and returns the results asap
- changed argument order of internal class IMapUnordered.
- new internal class IMap added to pool.py

add green version of getfqdn() to socket; add socket.__dns__ which lists all dns functions (for monkey)

libev: set backend_fudge to 1e-3 on Windows. Experiments show this is when sleep(0) stops busy looping and starts sleeping.

- also use 'def' instead of 'cpdef' for watcher methods on loop
there's no need for fast method to create a watcher since in C you can use libev directly

Fixed issue #63: monkey.patch_thread() now patches threading too, even if it’s already imported. Patch by Shaun Lindsay. (pulled from gevent-0.13)