First steps towards rbZoom
-Solves the lost of control of focus over containers
-Improves rbzoom activation
-keyevent from qvtkwidget are sent to medMainWindow enabling the
activation of shortcut via keypressevent and keypressrelease
Small changes
removes useless lines
-Now after choosing zoom as the main mouse interaction the focus is
directly brought back to the view.
- A new shortcut has been defined for the histogram
- This commit desactivates most of the key shortcuts that were existing in
  the code of vtkInria.
Removes useless lines
Resolves the rbzoom bug appearing when the ctrl key is pressed when the application loses focus