Replace shell script with config file

Pytest can use a .ini file to define command line defaults. Additional options and use are documented [here](http://pytest.org/latest/customize.html).

To test, run `py.test` or `py.test tests/test_commotion_router_admin.py`. Pytest should run the tests using the options defined in pytest.ini. If you see a list of the slowest tests in the results summary, the options are being applied.