1. Fix problem with canvas update 2. Mark current JSROOT version as 3.1

Signed-off-by: Bertrand Bellenot <bertrand.bellenot@cern.ch>
update JSROOT docu, use version 3.1 for links

Signed-off-by: Bertrand Bellenot <bertrand.bellenot@cern.ch>
remove log output

Signed-off-by: Bertrand Bellenot <bertrand.bellenot@cern.ch>