Added nodevisitor python example by Sébastien Barthélemy, exemplifies issues at i36
Added nodevisitor python example by Sébastien Barthélemy, exemplifies issues at i36

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extra : convert_revision : svn%3A9ea0355d-b33e-0410-9de5-817935624dc7/trunk%40216

cmbruns/osgswig,cmbruns/osgswig,cmbruns/osgswig,cmbruns/osgswig,cmbruns/osgswig