Per one of the diff comments on #1597:
> I used to use a tuple for constant things, but nowadays I'd actually
> prefer a list as a tuple is something more heterogeneous (i.e. it
> makes sense to have a `(x, y)` point as a tuple, but a list of points
> would be a list).
> At some point I should probably change it to a list everywhere 😉
* Don't flag attributes as unused if they are used as global variables in
another module.
* Don't consider "True" and "False" variable names.
* Abort with error message when invoked on .pyc files.
This means we can remove the whitelisted globals in run_vulture.py and
the associated xfailing test.
We also needed to adjust run_vulture.py slightly as the file attribute
got renamed to filename.
There are a lot of problems and flakiness with using a real clipboard.
Instead we now have a :debug-set-fake-clipboard command to set a text, and use
logging when getting the contents.
Fixes#1285.
