Option to save gdr images as fits.
Last details before branching.
Added multi box detection.

A rather arbitrary criterion: “good candidates” are this with max pixel
count above 1.5 * total field variance.
Completed boxes detection; more parameters into Interface.
Merge branch 'multiboxes'
Typos.
Multiple guiding boxes implemented.
Fix getting  Manager.
"$!#@ Got to do something about these typos...
Trying to debug install problem?
Merge branch 'multiboxes'