Implement toFixed() for Float

[Randy von der Weide]

I just found out that sciter does not have a toFixed function, and only has String.printf("%.1f", download_progress) as a substitute.
It might be nice to include a toFixed function in the future.

[Andrew]

It might be nice to include a toFixed function in the future.

Sure, just define it if you need that:

function Float.toFixed(frac) {
  return String.printf("%.*f", frac,this);
}

debug log: (3.1415).toFixed(2); // outputs "3.14"