Parliament demo update, CANDOR corpus conversion notebook (#201)

* fix use of mutability in Coordination transformer.

* run black formatter

* fixed coordination with efficient implementation

* comments for changes

* metadata field deepcopy

* documentation and website update for V3.0

* get dataframe mutation fix

* fix get dataframe mutability

* modify 3.0 documentation

* revert get dataframe fixes

* pairer maximize pair mode fix

* backendMapper, config documentation

* goodbye to python3.7

* release date update

* remove all storage reference

* update release date

* updated setup.py, README

* updated parliament_demo with correct cluster names, added CANDOR corpus conversion notebook

* add CANDOR corpus request url

* CANDOR Corpus documentation and conversion code

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Co-authored-by: Cristian Danescu-Niculescu-Mizil <[email protected]>