The abstract lock() and unlock() methods were added to the SurfaceData class
during development of 1.4 in the anticipation that they would be implemented
sometime in the future. However, we've never implemented these methods in
any of our SurfaceData subclasses. They're not really taking up much space,
but since they're abstract each subclass has to add an empty implementation,
which is potentially annoying/confusing for porters. Therefore, we should
probably just remove these methods (they can always be added in later).
###@###.### 2005-1-19 01:30:23 GMT