Updated Media Capture and Streams editor's draft

Hi

A new version of the editor's draft is available.

Dated version: http://dev.w3.org/2011/webrtc/editor/archives/20130320/getusermedia.html
Living document: http://dev.w3.org/2011/webrtc/editor/getusermedia.html

Changes include:
* Changed error code to be string instead of number.
* Added core of settings proposal allowing for constraint changes after stream/track creation.

Note that capabilities and source states will likely also be added at some point.  This version focuses on initial integration of constraint/setting changes.


Please review and provide feedback.

Dan Burnett (for the editors)