Add : STLExporter component for STL format export

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@9741 b7f1a160-662a-0410-a6d8-bea165342f16
added house of cards example written in python (the same scene as the c++ tutorial)

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@9742 b7f1a160-662a-0410-a6d8-bea165342f16