Merge branch '2.2' into 3.0

# Conflicts:
#	README.md

gns3server/controller/node.py

@@ -559,7 +559,7 @@ class Node:
 
         # None properties are not be sent because it can mean the emulator doesn't support it
         for key in list(data.keys()):
-            if data[key] is None or data[key] is {} or key in self.CONTROLLER_ONLY_PROPERTIES:
+            if data[key] is None or data[key] == {} or key in self.CONTROLLER_ONLY_PROPERTIES:
                 del data[key]
 
         return data