zoom with mouse wheel is not working

[Andrey Skvortsov]

Traceback (most recent call last):
  File "/home/developer/WorkData/PLC/beremiz/beremiz/editors/Viewer.py", line 3675, in OnMouseWheelWindow
    self.SetScale(self.CurrentScale + rotation, mouse_event=event)
  File "/home/developer/WorkData/PLC/beremiz/beremiz/editors/Viewer.py", line 859, in SetScale
    self.ViewScale = (ZOOM_FACTORS[self.CurrentScale], ZOOM_FACTORS[self.CurrentScale])
TypeError: list indices must be integers, not float

[Andrey Skvortsov]

a30dfc8 fix zoom-in/zoom-out using mouse wheel regression introduced by 2393:235f847be37e