This change updates the Enumeration primitive, adding a fresh
implementation and documentation. An updated unit test suite for the
primitive is included. Numerous changes to Enumeration usage across the
library are also included to comply with the updated implementation.
This change reorganizes the test suite, splitting it into two separate
test suites, one for unit tests and one for integration tests. The tox
configuration is also updated to reflect this change. Invoking tox now
runs the unit tests by default. A separate tox environment is used to
run the integration tests.
