allow properties w/ setters to work with persistable classes

tpers.py

@@ -81,6 +81,10 @@ class TPrs(object):
     __obj_setattr = object.__setattr__
     __obj_delattr = object.__delattr__
     def __setattr__(self, key, value):
+        prop = getattr(self.__class__, key, None)
+        if isinstance(prop, property) and prop.fset:
+            prop.fset(self, value)
+            return
         try:
             if self._fWriteToPersistent or key in self._persistent:
                 self._persistent[key] = value