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)

test__threadpool.py: avoid spurios 'switched unexpectedly' messages because if kill() that switched out

It was previously possible to do the same by removing the source
repositories. But that's not easy to do when installing with pip.

The following command now installs without the embedded libraries:

,----
| gevent_embed=no pip install gevent
`----

the codespeak.net page is a bit outdated.