Removed peak/background bounding boxes from GUI
Resolves #243 (closed)
With the addition of per-pixel integration region plotting, these bounding boxes are obsolete. Worse still, they are misleading since the represent a projection of the bounding box on a single frame, rather than the pixels that are integrated from that frame, and are as a result considerable bigger than the on-frame integration regions. They also resulted in a lot of clutter in the detector scene widget.