* Add `AUDITLOG_USE_BASE_MANAGER` setting configuration
* Adjust `LogEntry._get_changes_display_for_fk_field` behaviour for setting
* Adjust `log_update` and `log_m2m_changes` in `receivers.py` for setting
* Add `ModelManagerTest.test_use_base_manager_setting`
* Add entry in Usage documentation
* (In passing, fix a formatting issue in `usage.rst`)
The `AUDITLOG_USE_BASE_MANAGER` setting has a default of `False` to maintain
initial backwards compatibility with previous versions.