maybe fix warning where a controller is created without being linked

control/controllers.py

@@ -15,6 +15,7 @@ class Controller():
         self.input          = None
         self.target         = target
         self.range          = warning_range
+        self.input_label    = "WARNING: NO INPUT LABEL SET"
 
         self.reach_period_s      = reach_period_s
         self.refractary_period_s = refractary_period_s