[#172897841] Bug fix: Drag of attribute to subplot axis doesn't change the graph
[#172897841] Bug fix: Drag of attribute to subplot axis doesn't change the graph

* GraphController wasn't set up to get or deal with notifications from subplot axes

concord-consortium/codap,concord-consortium/codap,concord-consortium/codap,concord-consortium/codap,concord-consortium/codap