Function fpsCounter

fpsCounter(autoDisplay?: boolean, computeAfterFrames?: number): () => number
Calculates frames per second.

Returns a function which needs to be called at the end of each frame.
```
const fps = fpsCounter();

function loop() {
 fps(); // Calculate fps
 window.requestAnimationFrame(loop);
}

loop();
```
Parameters
- autoDisplay: boolean = true
  If true (default), prints out the FPS to the console
- computeAfterFrames: number = 500
  Calculates after this many frames. Higher numbers smoothes the value somewhat
Returns () => number
- Defined in fps-counter.ts:20