resolver_thread: set expected_errors to Exception because it is possible for DNS functions to raise UnicodeDecodeError

--HG--
rename : gevent/coros.py => gevent/lock.py

That way core is all about libev and can be disabled without also dropping set_exc_info.

fix patched test_threading.py to actually test monkey patched threads in subprocess (previoulsly it tested regular threads)

util/winvbox.py: remove the code that redirects the output of the processes run on guest machine to a file and the downloads that file. instead rely on virtualbox's ability to grab process (which is somewhat broken as eats some newlines. still it's simpler that way)