update AUTHORS

and move to AUTHORS.md
update docs with recent changes
update autogen_api exclusions
update README for 13.0
remove unused keys from setup.cfg.template
save config if fallback to /usr/local succeeds and is necessary

avoids doing it every time
update MANIFEST.in
bump version to rc
fix dirs in virtual-env
Merge pull request #317 from minrk/rc

Doc updates for 13.0 RC

Release Candidate time!