Another update to screen rotation and movement.
The top right icon on the gizmo now dictates what the arrows and central sphere do. There are two rotation modes (object rotation and twist rotation) and a movement mode (the centre sphere then acts like the replaced movement icon).
Moving left/right/up/down with object rotation will rotate the board in the given direction.
Moving left/right with twist will rotate the board anticlockwise/clockwise, where as up/down will rotate it up/down.
The rotation on the secondary mouse button has also changed. Dragging the mouse while holding the secondary mouse button differs the nearer the edge of the screen you are, the centre of the central square of screen acts the same as before. Dragging in the screen tram lines around the central square area now rotates the view. Between the central square area and the centre of the central square area there is a gradual transition from one type of drag to the other.