Sharing webcam with deviceId prefix

...ebutton-html5/imports/api/video-streams/server/helpers.js

...mports/api/video-streams/server/modifiers/sharedWebcam.js

...luebutton-html5/imports/ui/components/media/container.jsx

...ports/ui/components/multiple-video-provider/component.jsx

...ports/ui/components/multiple-video-provider/container.jsx

.../imports/ui/components/multiple-video-provider/service.js

...onents/multiple-video-provider/video-button/component.jsx

...onents/multiple-video-provider/video-button/container.jsx

...mponents/multiple-video-provider/video-list/component.jsx

...e-video-provider/video-list/video-list-item/component.jsx

...e-video-provider/video-list/video-list-item/container.jsx