Removed need to provide plots with project/workflow on creation, is instead injected by project itself when added to it.

system/project.py

@@ -35,7 +35,7 @@ class Project:
         """Notifies observers"""
         for observer in self._observers[key]:
             if modifier != observer:
-                observer.update(self,key)
+                observer.update(key)
 
     def set_selection(self,dim_name,selection):
         """Sets a current selection and notify observers"""
@@ -58,6 +58,8 @@ class Project:
             elif isinstance(d, plots.Plot):
 #                self.add_view(d)
                 self.data_tree_insert(None, 'view', d)
+                d.set_project(self)
+                self.attach(d, 'selection_update')
 
     def data_tree_insert(self, parent, text, data):
         tree = self.data_tree