Pausing video does not clear the onProgress timeOut

[whitegrey]

Mostly a visual issue, but when pausing the video, there will often be another "tick" of the seek bar since the onProgress timeOut isn't cleared.

[cookpete]

The timeout is deliberately not cleared, because we might still want to get updates to the loaded percentage even when paused. Perhaps two progress callback props are needed instead, like playProgress and loadProgress.

Or, an easier fix would be just to check for this.props.playing here, which would just not include the played property if the media is paused.