The class vtkInteractorStyleRubberBandPick allows selection of a
rectangular window, when 'r' is pressed, and selection of a 1x1
window, when 'p' is pressed.
1) Is there a way to get the key that is currently pressed (the
current selection mode)?
2) Is it possible to set the selection mode 'r' or 'p' in the
code (i'm using pyqt and would like to choose the mode by
checking a box in a gui)?