Merge with dash.js:
Added reset in URIQueryAndFragmentModel. need to clear information when attachSource is called on media player.
Chromecast inegration

Add MultiAudio + refactor buttons
BufferExtensions.js: set DEFAULT_MIN_BUFFER_TIME to 16s.
HTTPRequest.js: add bytesLength
DemoPlayer: add current measured bitrate information
Merge from dash.js: fix issue 226 - explicitly update buffer after seek
MssParser.js: corrected SegmentTimeline generation when 'd' is not set on chunks