v0.2.2 [Escherichia coli]

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