update to changes from mlz repo

- bug fixes in error.py
- add from * to raise statements
- fix py35 compatibility
- finalize omit_unchanged_within feature
- fix follwup bug (missing Param.override) in proxy.py

Change-Id: I621c01a0d5e1ec6696fb06f39666f3316fb53649

secop/protocol/dispatcher.py

@@ -60,12 +60,11 @@ def make_update(modulename, pobj):
 
 
 class Dispatcher:
-
-    OMIT_UNCHANGED_WITHIN = 1  # do not send unchanged updates within 1 sec
-
     def __init__(self, name, logger, options, srv):
         # to avoid errors, we want to eat all options here
         self.equipment_id = options.pop('id', name)
+        # time interval for omitting updates of unchanged values
+        self.omit_unchanged_within = options.pop('omit_unchanged_within', 0.1)
         self.nodeprops = {}
         for k in list(options):
             self.nodeprops[k] = options.pop(k)
@@ -84,7 +83,6 @@ class Dispatcher:
         self._subscriptions = {}
         self._lock = threading.RLock()
         self.restart = srv.restart
-        self.shutdown = srv.shutdown
 
     def broadcast_event(self, msg, reallyall=False):
         """broadcasts a msg to all active connections