Just changing the position of the function dimension

* I was trying to use it in another functions defined before it.
Fitting polygons tests
Function to get the external points of a contour
Namespace and functions to handle Points as features

* Function to fit a polygon on a contour.
* Function to get a bounding box of a list of Points.
Bounding box area calculation; macros to avoid reflections
Testing the aprox-area function