add vtkEventData class and support

This topic introduces support for events in VTK to pass a vtkEventData instance as their calldata. This instance can be used to hold event specific data that would otherwise complicate the render window interactor. The event specific data also allows us to have fewer vtkCommands as we do not need a specific command for each button on a controller but rather can include the controller button as data in the appropriate vtkEventData subclass.

Currently this is only implemented for 3D events but it could be updated to handle mouse, keyboard or other events as desired.