w3c/media-source

- Adds EventHandler attributes to MediaSource, SourceBuffer, and
  SourceBufferList
- Minor source whitespace and changelist formatting fixes.

-  Corrected revision history link for April 15th changes.
-  Expanded PTS in note
-  Updated publishDate

Added note to section 3.3 Track Buffers clarifying use of PTS, frame
durations and coded frame group start times in track buffers.

Restored the normative conditions for detaching from a media element,
and defined the future direction (algorithm externally called) in a
non-normative note.

…enced algorithm

Generalized the MediaSource detach algorithm so that it can be called
for other HTMLMediaElement conditions.

resource=#mediasource-detach

Added HTML51 reference.

Replaced InvalidAccessError with TypeError.
Also fixed unexpected tag errors from previous changes.

…at end of current coded frame group

Inserted random access point steps when the frame being removed has a
decode timestamp == the last decode timestamp for that frame's track.

…g undefined media segment header

…hen resetting parser state.

…stamp and clarify definition.

…ion timestamp.

…e() and .mode setter consistent with other algorithms.

…ng has changed.

…bute sourcing requirements.

…have a default value of [].