- removed the old test_remove_environment
- modified the create_fake_environment to current specs
- add tests for removing package_sets and releases

Resolve "declutter the top level log file"

Closes #28

See merge request !115

Add tests that check our argument parsing logic (and fix bug)

See merge request !113

- going the arguments provided by the user
- to the relevant function being called.

Added tests because I discovered a bug that the tests would have caught.

Add example for `get_available_releases`

See merge request !111

return available (i.e. released!) release versions

See merge request !110

from available package sets