Proposed fix for bug 25789.
Cleaned up the MediaStream API intro section (mainly MediaStream behavior that have moved to MediaStreamTrack).
The concept of MediaStreamTrack with a detachable source is now used throughout the spec (removed language saying that a MST could be disassociated from its track).
added issue note to constrainable pattern section that ideal is not yet defined
added issue note for applyConstraints that how undordered constraints are to be satisfied together is still under discussion.
added informative note that unknown required constraints may be dropped by WebIDL-based processors and that app authors should use getSupportedConstraints()
updated constraint examples
Merge branch 'ms_cleanup'

Conflicts:
	getusermedia.html
Merge branch 'propfixbug25789' of http://github.com/stefhak/webrtc-w3c into stefhak-propfixbug25789

Conflicts:
	getusermedia.html
Readded lost track-muted and track-enabled definitions.
Merge branch 'stefhak-propfixbug25789'
Made some more references to "muted" and "enabled" link to their definitions.
added stronger wording about need to use getSupportedConstraints() before setting constraints
Whitespace cleanup of webrtc.html
Whitespace cleanup of webrtc.css
Whitespace cleanup of webrtc.js
Whitespace cleanup of getusermedia.css
Whitespace cleanup of MediaRecorder.html
Whitespace cleanup of getusermedia.html