waitForEvent add param control_exceptions to filter logging for given exceptions

Updating waitForEvent in events.py with control_exceptions param for flow control (like abort etc.) exceptions that should not be logged and ignored. The reason being when the scan is aborted from sardana without stopping it raises AbortException which is expected and it should be catched and ignored. Implemented like this to pass the control exceptions because taurus does not import stuff from sardana like AbortException etc.