Contour edition

Edit an object contour using mouse interactions

The function ctr_editContour allows to edit
- a point
- a square
- a rectangle
- a circle
- an ellipse
- a polygon
- a spline curve
on a given image using mouse interactions. This function is usefull
to edit an object contour. The output is a matrix Nx2 where N is
the number of sample points of the associated polygon. Moreover, the function
allows to modify an existing point (square, etc.) if the associated
polygon is an input parameter. Run script test.m to have an example.