add (limited) support for VTK format,

to be used with GenerateRigid

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11330 b7f1a160-662a-0410-a6d8-bea165342f16
remove message - python GenerateRigid does not like it

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11331 b7f1a160-662a-0410-a6d8-bea165342f16
Compliant: fixing python Rigid.generate_rigid (obliged to write a tmp file, due to GenerateRigid API and MUST wait for the Popen command to finish, it is quite slow). TODO: directly bind GenerateRigid in python.
+ adding its test (comparing mass, com and diagonal inertia computed from meshes for several ellipsoids/cuboids/cylinders and several densities) TODO test principal axis basis 


git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11332 b7f1a160-662a-0410-a6d8-bea165342f16
Compliant: adding a dependency to GenerateRigid (it should not be shuch a strong dependency but generally it is needed)

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11333 b7f1a160-662a-0410-a6d8-bea165342f16
Compliant: fixing python generate_rigid in debug

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11334 b7f1a160-662a-0410-a6d8-bea165342f16