(de)Register consumer nodes at config node

In order for error messages to be catchable

src/matrix-delete-event.js

@@ -13,6 +13,7 @@ module.exports = function(RED) {
             node.warn("No configuration node");
             return;
         }
+        node.server.register(node);
 
         node.status({ fill: "red", shape: "ring", text: "disconnected" });
 
@@ -70,6 +71,10 @@ module.exports = function(RED) {
                 node.send([null, msg]);
             });
         });
+
+        node.on("close", function() {
+            node.server.deregister(node);
+        });
     }
     RED.nodes.registerType("matrix-delete-event",MatrixDeleteEvent);
 }