chrome throw a permission denied exception if screen sharing + audio sharing

add a test to remove audio sharing when starting screen sharing. I don't advise to force audio off in `setScreenCapture` since it would be surprising to lose audio when switch back to webcam sharing
Fix typo  isMozillia vs isMozilla
Merge pull request #24 from fbeauchamp/master

Masked out the audio component of a GetUserMedia when doing a screen share.
Recommend new users move to EasyRTC v1.0 (or greater).
Merge branch 'beta'

Resolved Conflicts:
	README.md
	api/easyrtc.js
disable css stylesheed auto inject in easyrtc.js
easyrtc.loadStylesheet doc that disable css stylesheet autoinject
easyrtc.loadStylesheet doc typo
Minor fixes to docs requested by Doug.
Split the table on the demos index page into "easy" and "technical" tables.
Added a note to the demos index page about starting two different windows.
Further note Doug wanted regarding installing client files.
Moved the self video and the controls to the top of the  other video instead of the bottom.
Added a note about limitations of webcams.
Fix #30 ReferenceError: easyrtcid is not defined
Fix #31 force new socketio connection
Cleanup and lint some easyrtc.js #32
Fix typo #32
Fix missing parameter #32
Merged conflicts
The private enableMediaTracks method wasn't namespaced properly.
Added disconnect button
added support for disconnect button.