add unittest for normal flipping module

git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1031 fdac6126-5c0c-442c-9429-916003d36597
remove normal flipping test

git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1032 fdac6126-5c0c-442c-9429-916003d36597
possible fix and readd normal flipping test

git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1033 fdac6126-5c0c-442c-9429-916003d36597
remove unittest again, since it has problems on some machines

git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1034 fdac6126-5c0c-442c-9429-916003d36597