correctly capture closed bugs
send HTML emails

The plain-text looks pretty bad, especially in a non-monospace view.
It's also horrendously wide due to all of the links.
Include PR's for buildbot-infra, too
Merge djmitche/buildbot-infra:changetime (PR #6)
Merge djmitche/buildbot-infra:infra-too (PR #10)
Merge djmitche/buildbot-infra:html-email (PR #7)