The original wait_layout was unreliable, because there are no guarantees
re order of arrival of the respective events. Still, TT's event handling
is basically deterministic, so as long as the host sent its messages
close enough to each other, the order worked out.
This is no longer the case with the introduction of loop.spawn: TT's
behavior is still deterministic, but now ButtonAck is processed *before*
the corresponding wait_layout, so the waiting side waits forever.
In the new process, the host must first register to receive layout
events, and then receives all of them (so the number of calls to
wait_layout must match the number of layout changes).
DebugLinkWatchLayout message must be version-gated, because of an
unfortunate collection of bugs in previous versions wrt unknown message
handling; and this interests us because upgrade-tests are using
wait_layout feature.
This deserves some explanation.
* tests were moved to separate python/tests subdir
* trezorlib was moved to python/src, so that it does not exist on
PYTHONPATH by default
(see https://blog.ionelmc.ro/2014/05/25/python-packaging/ for details)
* everything was updated to understand the new structure
* trezorctl was changed from a top-level executable script to a module
`trezorlib.cli.trezorctl` and is installed via the entry_points
mechanism.
This should make it work normally on Windows!
The package should be installable as normal through pip and pipenv, no
changes are needed on that side.
The source package from pypi will include unit tests. (Device tests were
completely moved out). Wheel will exclude them, because users don't need
them.
That shrinks the .whl from 520 kB to 270 - nice!
python: reorganize remaining unit tests
