Moving the respec menu underneath the bug filing.

This avoids overlap of these two boxes during spec development.
Merge pull request #114 from silviapfeiffer/moveRespecBugs

Moving the respec menu underneath the bug filing.
Define WebVTT cue identifiers as unique.

Closes https://www.w3.org/Bugs/Public/show_bug.cgi?id=24674.
WebVTT region identifier must also be unique.