## Alpha-shape algorithm in gmsh ?

Following issue #1084 (closed) about the delaunay traingulation it would be really great to have a way to obtain elements, facets from gmsh using the alpha-shape algorithm (which is based on a delaunay triangulation).

The alpha-shape algorithm is really simple: a simplex is kept in the alpha-complex if there exists a cirlce or radius sqrt(alpha), passing by all points of the simplex, which does not contain any other points of the set.

It would be really great to have a prototype of the form:

```
GMSH_API void alphaShape(const std::vector<double> & coord, double alpha
std::vector<std::size_t> & nodesInTetra,
std::vector<std::size_t> & nodesInBoundaryFacet);
```