exception handling in notify observers

KCG/base/backend/board/board_config.py

@@ -465,10 +465,16 @@ class BoardConfiguration(QtGui.QWidget):
         write = args[1]
         if observers is not None:
             for (who, callback) in observers:
-                callback(value)
+                try:
+                    callback(value)
+                except Exception as e:
+                    log.error('Observer Callback error: {}'.format(e))
 
         for cb in self._observers_for_all:
-            cb(key, value)
+            try:
+                cb(key, value)
+            except:
+                pass
 
         if write:
             observers = self._observers_write.get(str(key), None)