fix parameter inheritance using MRO

+ no update on unhchanged values within 1 sec

Change-Id: I3e3d50bb5541e8d4da2badc3133d243dd0a3b892

test/test_iohandler.py

@@ -71,6 +71,8 @@ class Data:
 
 
 class DispatcherStub:
+    OMIT_UNCHANGED_WITHIN = 0
+
     def __init__(self, updates):
         self.updates = updates
 
@@ -106,7 +108,6 @@ def test_IOHandler():
     group1 = Hdl('group1', 'SIMPLE?', '%g')
     group2 = Hdl('group2', 'CMD?%(channel)d', '%g,%s,%d')
 
-
     class Module1(Module):
         channel = Property('the channel', IntRange(), default=3)
         loop = Property('the loop', IntRange(), default=2)