grep 
TO BE MOVED TO KERNEL
TODO

ajouter 
-	Function Object Concept SphericalKernel::ConstructLine_3
	Line_3 fo.operator()(Circular_arc_point_3 p1, Circular_arc_point_3 p2)
- same for Line_arc_3

============
---- from Daniel

- the arc point/plane orientation--I can't publicly get a  Root_for_spheres_2_3 back from a circular_arc_point so I can't  implement it myself either
- a way of getting a line through a circular_arc_point. I think I  really need this, at least I use it extensively and don't see an  obvious way around it.


- the ability to negate a particular coordinate of a arc point--this  is a bit idiosyncratic, perhaps the ability to apply some subclass of  affine transform
- a way to check for the intersection of three spheres (I can do 2  using the linear kernel)--I can presumably work around this though
- the output iterator based intersect is even more annoying than the  normal intersect. 
============

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nettoyer 
Solve 
critical points
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? deplacer       
typedef std::pair< Polynomial_for_spheres_2_3, Polynomial_1_3 >
                                                 Polynomials_for_circle_3;
dans AK ? (c'est dans SK)

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remplacer les std::acos(-1.) par CGAL_PI

filtered bbox kernel (voir TODO CK2)
Exact_circular_kernel_3
Lazy
tests for those

check do_intersect(sphere,sphere): should be in Kernel, our local 
version uses alg. nbs..

changer les noms des polynomes (cercles et droites) dans le code... 

cercle par 3 points

--> a transferer dans linear kernel 
        - unoriented equal (pb general orientation dans noyau cgal...)
        - intersection de deux Line_3
        - radical plane
        - calculs de longueurs et surfaces

intersection arcs/triangle

spherical patch 'triangle'
(NB: package Curved_kernel dans branch/cannot_wait...)