Adding Video Setting component

- Importing source code in `index.html`
- Updated `app.js` to add video setting as dependency for style guide app
- Updated `controllers.js` to add video setting to `$scope.uiComponents` and value for `$scope.video`
- Added demo html file
- Added `video-setting.js` to libs
- Including video setting in `bower.json` under the other components listed for `widget-settings-ui-components` repo