[API change] Renamed default convergence criterion from VDB to Default
Renamed exit status of GJK (no API change, only used internally)
Removed useless function I previously introduced in EPA
If EPA encounters badly conditioned problems, do not return nans. Often, the Degenerate, NonConvex and InvalidHull cases, the estimate of the normal and penetration depth is not the best but it's better than returning nans.
Multiple little GJK/EPA modifications:
VDBtoDefaultDegenerate,NonConvexandInvalidHullcases, the estimate of the normal and penetration depth is not the best but it's better than returning nans.