Because strange behaviour with Qt::key_space if used for keyPressEvent
and also in shortcut.
Now the shortcut for the rotate action is ctrl + R and key_space to
rotate terminal on the fly before placing it in the drawing.
* Some types of elements need to specialize the setRotation method in order to behave correctly :
- PartTerminal needs to call setOrientation
- PartLine, PartRectangle and PartPolygon need a different rotation center.