On windows, it seems that the generated tahoe.exe (which comes
via entry_points=) doesn't deal with signals nicely. I'm not
sure if this is a pip bug (or just "one of those Windows things")
but running with python -m allows us to kill our subprocesses.
This introduces a py.test-based integration suite (currently just
containing magic-folder end-to-end tests). Also adds a tox environment
("integration") to run them.
The test setup is:
- a "flogtool gather" instance
- an Introducer
- five Storage nodes
- Alice and Bob client nodes
- Alice and Bob have paired magic-folders
