ssl.py bug fix: in certain cases, exc_clear() was followed by 'raise', causing TypeError. Issue #124. Thanks to Johan Mjones.

test__pywsgi.py: move subclass into global scope so that refcount test passes. remove get_wsgi_module() function

testrunner.py: make sure we kill the whole tree on Windows; do not use mysubprocess; allow per-file timeouts

update gevent/libev_vfd.py: remove GEVENT_VFD_MODE, it's no longer needed. import winsock2.h instead of winsock.h

 - install SIGCHLD lazily when first child watcher started
 - properly call WSARecv
 - log WSARecv's and WSASend's errors;
 - install periodic timer for waitpid()
 - ev_loop_destroy(): do not stop childev watcher when destroing non-default loop

add xtest_signal.py which reproduces SIGCHLD being missed (fixed in https://bitbucket.org/denis/gevent/changeset/adb8b5ac698c)