webapp/printing sagews: error handling when downloading videos for embedding; some cleanup and commenting
webapp/printing sagews: error handling when downloading videos for embedding; some cleanup and commenting

tscholl2/smc,DrXyzzy/smc,DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,sagemathinc/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc