bugs in example 16

[rpoleski]

• Delta t_0 is not saved anywhere

Things that are borderline between bug and missing enhancement:

• print script version
• save fixed parameters
• warnings if plots will overwrite existing files

[rapoliveira]

@rpoleski I have addressed all the bugs/improvements listed here. Moreover, I added a boolean option to the yaml input file, under "second Y axis" of the best model plot, in order to recalculate the magnifications if the provided list is out of range.

Please take a look at it and send any suggestions before I make the pull request.

[rpoleski]

Nice job!
I would suggest one change. You added a new option recalculate magnification ticks. There will be a problem if the user provides both that and magnifications: which one should be used? I would suggest not to add that option, but instead allow, e.g., magnifications: optimal. And second thing (sic!) - if optimal is provided, then labels are not allowed.