Exit with non-zero exit code when unit tests fail
Add load_custom_filters() module-level function
Add CUSTOM_FILTERS module-level variable
Add CUSTOM module-level variable
Add CUSTOM to Passband.ALL_SYSTEMS
Add tempinput() context manager
Add Passband.__init__custom()
Update Passband.__init__()
Update docstring of Passband.__init__()
Update Passband.all() class method
Update docstring of Passband.all()
Update Passband.__str__()
Update docstring of Passband.__str__()
Update Passband.__cmp__()
Update docstring of Passband.__cmp__()
Update Passband.random() class method
Update docstring of Passband._parse_name()
Update Passband class docstring
Update NonRecognizedPassband.ERROR_NOTE class variable
Add PassbandTest.test_custom_filters()