curves / contour slicing to use the interpolating isosplit cgal feature

[jf---]

the recent compas_cgal additions use the

CGAL::Polygon_mesh_processing::refine_mesh_at_isolevel

method in isolines interpolation.

from compas_cgal.geodesics import HeatGeodesicSolver
from compas_cgal.geodesics import geodesic_isolines
from compas_cgal.geodesics import geodesic_isolines_split
from compas_cgal.geodesics import heat_geodesic_distances

likely the contour and curve slicing could benefit from these

---

see PR #183

[jf---]

done