Locus continuous function : Continuity tests using the following enum values are identical to tests using the preceding enum values on the INTERIOR of a curve's domain. At the END of a curve a "locus" test is performed in place of a parametric test. In particular, at the END of a domain, all open curves are locus discontinuous. At the END of a domain, all closed curves are at least C0_locus_continuous. By convention all Curves are considered locus continuous at the START of the evaluation domain. This convention is not strictly correct, but it was adopted to make iterative kink finding tools easier to use and so that locus discontinuities are reported once at the end parameter of a curve rather than twice.
