- Add git_data_canonical_authors module with maps various
"Author <email>" combinations to a single author.
- Add git_data_sha1_override_authors module which
overrides authors for individual commits.
- GitCommit.author now includes the email.
- Move co-author access into GitCommit.co_authors.
Using name & email, then de-duplicating removes 43 duplicates in the
generated credits.
Moving the author & override mapping out of credits_git_gen.py
allows this data to be shared by a utility to update AUTHORS
(not yet committed).
