This revision adds several changes:
New Transform tab:
The Rotation option passed to this new tab and 4 new options, Skew X and Y, Mirror X and Y are added
Button Add shape
The button Add shape is no longer in the Shapes tab, so you can add the form from any tab.
Added checkbox Square selection, to change from a rectangular to a square selection, and also avoiding the duplication of forms, Rectangle/Square and Ellipse/Circle, the Square and Circle objects are achieved with Rectangle or Ellipse objects + Square selection
Numeric fields now support math and W and H shortcuts (uppercase, W = width and H = height of the current image), so if we want any of the values is half the height of the image would write “H/2″