[MSE] Spec updates published

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

Summary of changes:

Change 1
- Remove early abort step on 0-byte appends so the same events fire as a
normal append with bytes. (Bug
20759<https://www.w3.org/Bugs/Public/show_bug.cgi?id=20759>
)
- Added definition for 'enough data to ensure uninterrupted playback' (Bug
18592 <https://www.w3.org/Bugs/Public/show_bug.cgi?id=18592>)
- Updated buffered ranges algorithm to properly compute the ranges for
Philip's example. (Bug
18615<https://www.w3.org/Bugs/Public/show_bug.cgi?id=18615>
)

Change 2
- Make remove() asynchronous. (Bug
20758<https://www.w3.org/Bugs/Public/show_bug.cgi?id=20758>
)
- Modified a few algorithms to throw an INVALID_STATE_ERR exception when
there are pending async operations.

Diffs:
https://dvcs.w3.org/hg/html-media/rev/aae26333e7d1
https://dvcs.w3.org/hg/html-media/rev/b35722b0cd8f

Aaron