syncstring: improve logging and fix so that poll interval reacts to existence of updates
syncstring: improve logging and fix so that poll interval reacts to existence of updates

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