[MSE] Spec Updates Published

I have published updates to the Media Source
Extensions<https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html>
 spec.

I'd like to name this the "Make Cyril Happy" Release since all the bugs
I've addressed were filed by him. :) Thank you Cyril for your attention to
detail and helpful suggestions.

Summary of changes:
Bug 25157 <https://www.w3.org/Bugs/Public/show_bug.cgi?id=25157> - Fix typo
in coded frame duration example.
Bug 24854 <https://www.w3.org/Bugs/Public/show_bug.cgi?id=24854> - Moved
negative timestamp checking to allow "sequence" mode to handle appending
coded frames in reverse order
Bug 24820 <https://www.w3.org/Bugs/Public/show_bug.cgi?id=24820> - Renamed
highest presentation end timestamp to group end timestamp and fixed a few
related issues.

Diffs:
https://dvcs.w3.org/hg/html-media/rev/d471a4412040

Aaron