ENH: added new example notebook for selecting different ROI shapes
ENH: added new example notebook for selecting different ROI shapes

scikit-beam/scikit-beam-examples,sameera2004/scikit-xray-examples,sameera2004/scikit-beam-examples,scikit-xray/scikit-xray-examples,Nikea/scikit-xray-examples,hainm/scikit-xray-examples