Add candidate change and insertions relating to previously merged class-3 changes. (#616)

* Add candidate change and insertions for #380/#388.
* Reorder change details with newest first.
* Comment out 2021-01-05 editorial changes to node-map-generation algorithm.
* Comment out 2021-02-25 editorial changes to IRI expansion algorithm.
* Add Candidate Correction 2 for issue #514.
* CANDIDATE CORRECTION 3 for issue 565, PR 566 to "Fix context processing for reverse terms".
* CANDIDATE CORRECTION 4 for `extractAllScripts` option to `toRdf()`.

Author: gkellogg