Fix for recursion bug on rdfa.info/play (Issue #46)

Hi!

I took the liberty of addressing a bug in the visualization tree at rdfa.info/play where links to an ancestor (or the node itself) would cause infinite recursion. The issue was already reported on Github as issue #46 (https://github.com/rdfa/rdfa-website/issues/46 <https://github.com/rdfa/rdfa-website/issues/46>). My pull request is at https://github.com/rdfa/rdfa-website/pull/47 <https://github.com/rdfa/rdfa-website/pull/47> and has some more details/examples of what causes the bug.

On a related note, there doesn't seem to be a lot of activity in the repository/the website, is it still actively maintained? The README still suggests contributions/fixes should be notified to public-rdf-wg@w3.org – which has been closed...

Take care,

Victor Andrée