Switch to pytest

* [x] use pytest markers
* [x] use pytest for runtests and ci tests.
* [x] remove the `pytest_tools` directory.
* [x] remove `run_module_suite` from the test files.
* [x] fixup the remaining yield tests, warnings currently suppressed in ci testing.
* [x] test for nose dependencies by removing nose import from some ci tests.
* [ ] update documentation
* [x] update `numpy-wheels`
