Compliant: put assembly helper functions in a separated file

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@9900 b7f1a160-662a-0410-a6d8-bea165342f16
update Flexible and Image: Improved voronoi-based shape functions (subpixel voronoi frontiers localization)

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@9901 b7f1a160-662a-0410-a6d8-bea165342f16
Corrected point generation using hexahedral barycentric coordinates

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@9902 b7f1a160-662a-0410-a6d8-bea165342f16
Flexible: added RigidConstraint component

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@9903 b7f1a160-662a-0410-a6d8-bea165342f16