Refactor dist-git releasers to separate module.
Add support for checking bz flags.
Fixes for Python 3.
Hookup bugzilla flag checking with dist git releasers.
Add documentation for bugzilla flag checking.
Merge branch 'bzflagcheck'

Conflicts:
	hacking/titotest-centos-5.9/Dockerfile
Fix failing tests with no ~/.bugzillarc.
Style fixes.