Check feasibility after a restoration failure?

[Robbybp]

One of my pet peeves with Ipopt is that it returns a Restoration_Failed status code even when it fails at a feasible or almost feasible point. In many applications and algorithms, a feasible solution is fine, and Restoration_Failed makes it seem like something is seriously wrong with the termination point. I encounter this often enough that I'd like to do something about it.

IMO Ipopt should use the Feasible_Point_Found status in these cases (or a similar status for "acceptably feasible"). Barring that, we could handle "(almost) feasible restoration failures" in this interface. My proposal would be to check primal feasibility if we encounter a restoration failure and return MOI.LOCALLY_SOLVED, MOI.ALMOST_LOCALLY_SOLVED, or MOI.LOCALLY_INFEASIBLE as appropriate.

[odow]

Closed by #435