#629 Report both minimum and maximum where possible

[David Benn]

A couple of CHOICE VStar VIII participants wondered why only one extremum value was reported from polynomial fits, e.g. see https://www.aavso.org/comment/60363#comment-60363

In principle, both should be.

[David Benn]

See also the May 2019 CHOICE course:

https://www.aavso.org/comment/64810#comment-64810