Fix warnings reported when running unit tests via pytest.
- Rename TestDevice to MockDevice, so that it is not interpreted as a
test case.
- Fix collections abstract base class imports.
- Add an ini file to ignore the same from "past".
- Add copyright headers to files that did not already have them
- Update the year to the last year the file was modified in files with
existing headers.
The current test was designed to test the removed `Agenda` class, we now
use use an `AgendaParser` so update the tests to test its functionality
instead.
Tests now reside in the root of the repo, rather than in wa package.
This means they will no longer packaged and installed in user
deployments (they're only useful for developers).
