Removed the ProvRecord._extra_attributes
ProvRecord._attributes now holds both PROV attributes and the extra attributes: dict(QName -> Set)
Added back missing original test files
Added ProvDocument.flattened()
Added printing out PROV-N of bundles in a document
Added simple unification of records based on their names
Updated DOT generation to 1.x prov.model
- Renamed prov.graph to prov.dot
- Showing n-ary relation in the graph as default
Added setup.cfg
fix: rename contants -> constants
enh: first pass at serialization
remove debug print
starting deserialization
enh: updated to reflect latest upstream changes for attributes, added bundle support