[MSE] Spec updates published

I posted more changes to the Media Source
Extensions<http://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html>
spec
yesterday.

Summary of the changes:

- Rework byte stream format text so it doesn't imply that the
MediaSourceimplementation must support all formats supported by the
HTMLMediaElement. (Bug
19531<https://www.w3.org/Bugs/Public/show_bug.cgi?id=19531>
)

- Remove 2.x subsections that are already covered by algorithm text. (Bug
18575 <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18575>)

- Added unique ID generation text to Initialization Segment Received
algorithm. (Bug 18960 <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18960>
)

- Reworked Initialization Segment Received algorithm so track creation is
more explicit and behavior differences between the first init segment and
later ones is clearer.

- append() now throws a QUOTA_EXCEEDED_ERR when the SourceBuffer is full. (Bug
18963 <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18963>)

Diffs: http://dvcs.w3.org/hg/html-media/rev/43be42e69533

Aaron