Add parsing capability to recognize the flags [incr] and [no-qa] in the PQM commit message

[Ursula Junque]

We're adopting two new flags in the PQM commit message: [incr] and [no-qa].

[incr]: This means that the commit is part of a larger goal, like a big feature or complicated fix. We shouldn't mark the bugs as Fix Committed, only add a message saying a commit is part of its fix. Also, in this case, we should check if there are bugs related and if not, send out emails. That's another bug I have to file.

[no-qa]: This means we don't have to care about that commit, because it's something we don't need to QA. When finding this flag and a bug number, we should add it the tag "qa-untestable" tag.

This needs to be implemented:

[no-qa] + [bug=...] : bug is marked as qa-untestable, not qa-needstesting
[no-qa] : branch is OK to be an orphan (no bug)
[incr] + [bug=...] : we do not add a tag to the bug or change its state (and, later, note that branch is an incremental change for a QA report)
[bug=...] : bug is marked as qa-needstesting, as now.