Reto Stockli - 2016-05-29

Based on Gilles and Alain's recommendations from our e-mail exchange in 2015 I've added a simple C interface to the QHULL library (which I wrote and tested offline from gdl) for the triangulate function. This interface provides basic triangulation. The xval&yval input data from gdl is successfully triangulated. Not being a GDL developer, I'm not sure how to return the triangulated vertices back to GDL. I'm happy to learn from you and can then possibly add the other QHULL functionality (vornoi, qhull etc.).

Please find attached my suggestion.