Rename ADT_Area to ADT_BoundingBox

[Addono]

Better reflects the naming used in papers, although it does allow slightly more than most bounding boxes since they often have finite width and height while our area also allows infinity.

[akbokha]

I am fine with the renaming of course. BoudingBox/EnclosingRectangle is indeed a less ambiguous name in our context. I would not be too worried about naming issues.