add details on voicing people
minor edits to compatibility policy
minor edits to eight policy
remove reference to maintainers, and to buildbot.net admin
update release policy

* update the locations where things are announced/uploaded
* reference semver
* remove the promise for "exceptionally stable" releases
Send security inquiries to Botherders, not a list in MAINTAINTERS.txt
formatting
Merge pull request #2 from djmitche/policy-updates

Policy updates