Questionable utility of the +/- 5 image display of predictions

[dagewa]

DUI's behaviour of showing predicted positions on images +/- 5 (or is it 3?) from the centroid is unusual (other diffraction image display programs don't do it) and incurs significant extra overhead calculating overlays (see #8).

I would prefer that this feature is removed unless it can be re-implemented in a way that is very fast and does not cause confusion, cf.

It’s also a bit misleading as the boxes don’t have spots in them - which I guess is because of the +/- 5 images thing in preference to using the actual reflection width?