jupyter: support SMC's autosave
jupyter: support SMC's autosave

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