New home for Tioga

Now, it's been a long time since Rubyforge has become unusable, and the Tioga project (on which ctioga2 is based) was still hosted there. I first wanted to thanks Rubyforge for hosting our projects for so long, and then say that Tioga is now maintained in sourceforge in a git repository. The web page is hosted by sourceforge as well, and that includes the documentation. A clone of the git repository is available on github. Enjoy !