* Migrate to pytest
All tests were update to use pytest.
Tests were alse black formatted. Eventually all code
will be black formatted but need to merge some PRs first.
- 'clear' polarity primitives no longer erase background
- Added aperture macro support for polygons
- Added aperture macro rendring support
- Renderer now creates a new surface for each layer and merges them instead of working
directly on a single surface
- Updated examples accordingly
