pyMPTK: implement book __getstate__ and __setstate__, to allow python copying
pyMPTK: implement book __getstate__ and __setstate__, to allow python copying

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/mptk/trunk@2105 0f77665a-23fb-0310-bc23-e91fd8efc3e1