Splits quad or polygon faces into triangles.

Implemented using naive face triangulation - builds a triangle fan anchored at the first face vertex.

`triangulate(faces | geometry)`

Parameters:

`faces`

- list of face indices e.g. `[[0,1,2,3], [3,2,5,4],...]`

`geometry`

- simplicial complex geometry `{ positions: [], cells: [] }`

Returns:

If `faces`

is supplied a list of triangles will be returned.

If `geometry`

is supplied a new geometry with cloned positions and triangulated faces will be returned.

```
var triangulate = require('geom-triangulate');
var faces = [[0,1,2,3], [3,2,5,4],...];
var tris = triangulate(faces); //[[0,1,2], [0,2,3], ...]
```

MIT, see LICENSE.md for details.