http://cg.ivd.kit.edu/svgf.php :))

Is it possible to turn this into an API that can be used for other 3D models.

Something like this gloriously oversimplified pseudo-code:
// set 3D scene
var threeDeeModel = [3dScene];

// add scene to pathtracer
pathTracer(threeDeeModel);

The description mentions

To calculate a pixel color, a ray is shot into the scene and allowed to bounce around five times. At each bounce, the direct light incoming at that point (including shadows) is multiplied by all previous material colors and accumulated. Soft shadows are achieved by randomly jittering the light position per-pixel.

That sounds more like a small extension to ray tracing. With path tracing, rays should bounce around until they hit a light source and soft shadows should occur naturally. The point of path tracing is that tricks like jittering light positions are not necessary. Admittedly, the advantage of your implementation is that the quality improves really quickly, but it does not appear to be a real path tracer.