Adding support for sceneIO. Therefore several classes are now able to generate XML definition strings.

git-svn-id: http://svn.code.sf.net/p/simox/code/trunk@215 042f3d55-54a8-47e9-b7fb-15903f145c44

git-svn-id: http://svn.code.sf.net/p/simox/code/trunk@146 042f3d55-54a8-47e9-b7fb-15903f145c44