------------------
Added
+++++
- ``Lineage.taxid`` property and tests
- ``NodesModel``, ``LinksModel`` and ``NetworkmetadataModel``
- ``Network`` class to read, write and manipulate networks and tests
- 'network_files' and 'correlation_data' fixtures for tests
Changed
+++++++
- Keys for ``MetadataType`` class
- Incorporate new keys in 'metadata.json' in test data
- Changed ``MetadataType`` from 'BaseType' to 'Model'
- Renamed ``MetadataType`` -> ``MetadataModel``