Capturing input events

Input events on the UI which do not interact with specific Qt components are handled by ddPythonEventFilter.h as the base object, but this only passes on events using the handleEvent(QObject*, QEvent*) signal.

This signal is caught by viewEventFilter.py, which is instantiated when robotsystem's initViewBehaviors function is called by the director startup to create the RobotViewBehaviors object which contains RobotViewEventFilter, a subclass of ViewEventFilter.

The filterEvent function of ViewEventFilter calls functions depending on the type of event that was received.