[python] QVTKRenderWindowInteractor crashes on non-standard key-press ( _ for example )
Running the following code:
from vtk.qt import QVTKRenderWindowInteractor
QVTKRenderWindowInteractor.QVTKRenderWidgetConeExample()
and pressing _ (shift + '-') crashes the program.
This is because '_' is not in _keysyms and thus _qt_key_to_key_sym returns None.