Challenging interpolation sets.

[wildsm]

In rare cases, after a subproblem solution has been evaluated, pounders will produce an interpolation set with with fewer than n+1 points. This is because the order in which points are examined for sufficient affine independence is reverse lexicographic.

A test case illustrating the issue on the main branch is in #149.

This is not a bug in formquad, but an issue with pounders assuming that, since the trust region radius and center have not changed and the model is not valid, a model-improving point will be evaluated; after no more than n-1 such iterations, the model will be valid and progress will be made (either through accepting a solution in the mean time, or having a valid model, which then allows the radius to shrink).

Multiple fixes are given below.

[wildsm]

One simple fix is shown here:
main...bugfix/safeguarding_Mind_1

[wildsm]

The alternative version is here:
main...bugfix/safeguarding_Mind_2

[wildsm]

@jared321 prefers main...bugfix/safeguarding_Mind_1 but with a bit more documentation on the ordering change (ie., what is Par(5) and how and why should one use it)
@wildsm agrees and will address