Removed support for callable default values.
Fixed handling of lists of FieldDefinitions.
Documented StoragePluginInterface class.
Updated Extraction, PostProcessing and Validation Plugin Interfaces to reflect that data is expected to be taken and returned as a list of (UID value, ExtractedDataItem instance) tuples rather than a dict mapping UID value to ExtractedDataItem instance.
Updated Extraction CLI script to expect a list of (UID value, ExtractedDataItem instance) tuples rather than a dict mapping UID value to ExtractedDataItem instance.
Moved generate_field_value and generate_data_template functions to module scope.
Improved custom JSONEncoder.
Implemented SQLAlchemy logging support.