message: Implement get_bounds(triangle)
diff: // See the LICENSE file for details.
  #include "../aabb.h"
  -
  +#include "../rectangle.h"
  namespace MATH_NAMESPACE
  {
  @@ -50,6 +50,20 @@ basic_aabb<T> get_bounds(basic_triangle<Dim, T, P> const& t)
  return bounds;
  }
  +template <typename T, typename P>
  +MATH_FUNC
  +rectangle<min_max_layout<2, T>, T> get_bounds(basic_triangle<2, T, P> const& t)
  +{
  + rectangle<min_max_layout<2, T>, T> bounds;
  +
  + bounds.invalidate();
  + bounds.insert(t.v1);
  + bounds.insert(t.v1 + t.e1);
  + bounds.insert(t.v1 + t.e2);
  +
  + return bounds;
  +}
  +
  template <size_t Dim, typename T, typename P, typename U, typename Generator>
  MATH_FUNC
  inline vector<3, U> sample_surface(basic_triangle<Dim, T, P> const& t, U& pdf, Generator& gen)
  