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)

- version-neutral syntax for print and exec
- version-neutral exception handling: use exc_info()
- version-neutral exception raising: use raise A("x"), not A, "x"
- use e.args[0] instead of e[0]
- use urllib.request if urllib2 unavailable
- use http.client if httplib not available
- use socketserver if SocketServer not available
- use test.support if test_support not available

greentest/helper.py: try test.support if test_support is not available (py3k). Patch by Damien Churchill.