Made changes to NodeSet API and started work on keep a "current selection" node set up-to-date in the DB for every data set.
Merge branch 'node_relationship_ui_feature' of github.com:parklab/refinery-platform into node_relationship_ui_feature
Fixed redirect issue with external tool status resource.
Added support for update and delete.
Removed Guardian permission checks.
Updating current node set on all updates to selection.