make it possible to debug "Store has a cycle in its computed values" (https://github.com/sagemathinc/smc/issues/1267)
make it possible to debug "Store has a cycle in its computed values" (https://github.com/sagemathinc/smc/issues/1267)

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