Compliant: optimized a whole bunch of map lookups during assembly

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@9687 b7f1a160-662a-0410-a6d8-bea165342f16
Compliant: added callback system to assembly visitor to customize assembly from other classes (typically OdeSolver/LinearSolver)

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@9688 b7f1a160-662a-0410-a6d8-bea165342f16