Add manifest.webapp for FirefoxOS

to test GetUserMedia with constraints
Offser nicer look for RTCPeerConnection test

Video element will be displayed side by side along with screen resolution.
Add simple shim of RTCPeerConnection for Firefox

Parameter of createOffer also changed for Firefox.
The method call occurs exception about insufficient parameters without it.
Developer info is added
Add manifest.webapp for FirefoxOS at rtcpeerconnection
Add icons for webapps