Convex hull object implementation

Included in ``convex_hull.py`` file as two additional functions.
``connected_components(image, start_pixel_tuple)``: Computes the object connected to ``start_pixel_tuple`` and returns a ``bool` array of same size as ``image`` but with only that 1 segmented object.

``convex_hull_object(image, output_form)``: Given a binary image, it computes the convex hull of the individual objects. For return, it can either return a 2D binary image with all the individual convex hulls or return a 3D array with segmented convex hull for each object.