message: Fix degeneracy check in Plane
diff: @@ -282,7 +282,7 @@ Plane<T, NDIMS>::Plane(const T* x1, const T* x2, const T* x3)
  // check for degenerate line or triangle
  bool degenerate = normal.is_zero();
  - SLIC_CHECK_MSG(degenerate,
  + SLIC_CHECK_MSG(!degenerate,
  "Supplied points form a degenerate "
  << ((NDIMS == 2) ? "line" : "triangle"));
  