Serious problems with reviewed code sometimes need a way to indicate that parts must be fixed before a checkin, this code change attempts to create a solution for that by allowing a reviewer to mark an inline comment as "submission blocking".

A the review requester can still select "submitted" if comments have been marked as submission blocking but never fixed.  We did not want to prevent that because it creates a potential workflow issue.

This has bugs right now but I wanted to get feedback as soon as possible.

Bugs I'm trying to verify/fix:

  * Existing comments, when clicked on, do not indicate they were marked as blocking in the pop up blue dialog box.
  * "Ship it!" is still available to a reviewer who has marked a comment as blocking.  It should not be available to be chosen if that reviewer marked something as submission blocking.

Locally against alpha 1.1 tip.