Use a class to hold all the manhole configuration state (work-in-progress).
Fix the dependency issues. Correct some more internals tests.
Rename `cry` to `Logger/_log`. Move the single instance checks outside (also remove metaclass). Some other renaming, small fixes ...
Use specific exception classes.
Document the Logger object. Rename it's attributes: `verbose` to `enabled`.
Do manhole configuration after the global instance is assigned (and the single-instance checks critical section is done).
Rename _log to _LOG (to be consistent with the _MANHOLE name).
Pretty up.
Actually the logging conf doesn't need to be in the critical section.
Make ALL_SIGNALS private

It is not documneted and it does not make sense that manhole will
provide this interface.
Use `python3` instead of `python3.4` for check/report envs.
Rename cry to log.
Update ignores.
Merge remote-tracking branch 'origin/master' into way-less-globals