Document fullscreen callbacks fix #861

       playWhenInactive={false}                // [iOS] Video continues to play when control or notification center are shown.

       ignoreSilentSwitch={"ignore"}           // [iOS] ignore | obey - When 'ignore', audio will still play with the iOS hard silent switch set to silent. When 'obey', audio will toggle with the switch. When not specified, will inherit audio settings as usual.

       progressUpdateInterval={250.0}          // [iOS] Interval to fire onProgress (default to ~250ms)

       onBuffer={this.onBuffer}                // Callback when remote video is buffering

       onEnd={this.onEnd}                      // Callback when playback finishes

       onError={this.videoError}               // Callback when video cannot be loaded

       onFullscreenPlayerWillPresent={this.fullScreenPlayerWillPresent} // Callback before fullscreen starts

       onFullscreenPlayerDidPresent={this.fullScreenPlayerDidPresent}   // Callback after fullscreen started

       onFullscreenPlayerWillDismiss={this.fullScreenPlayerWillDismiss} // Callback before fullscreen stops

       onFullscreenPlayerDidDismiss={this.fullScreenPlayerDidDissmiss}  // Callback after fullscreen stopped

       onLoadStart={this.loadStart}            // Callback when video starts to load

       onLoad={this.setDuration}               // Callback when video loads

       onProgress={this.setTime}               // Callback every ~250ms with currentTime

       onEnd={this.onEnd}                      // Callback when playback finishes

       onError={this.videoError}               // Callback when video cannot be loaded

       onBuffer={this.onBuffer}                // Callback when remote video is buffering

       onTimedMetadata={this.onTimedMetadata}  // Callback when the stream receive some metadata

       style={styles.backgroundVideo} />