* Add missing method to query the type of a light
* IcoSphere now generates front facing triangles
* Add a fairly generic sphere object to use in samples
it provides an ico sphere with normal, and reuses
the same vertex/index buffer for each new instance.
Each instance can have its own material, size and
position.
currently it’s not possible to change the # of
subdivisions.
* FilamentApp now provides a “default” pbr material
this makes it easier to create renderables for
testing.
* clean-up lightbulb and add spheres for each light
lightbulb now has less hardcoded things and it
spawns a small sphere for each light.
