Allow for an initial render or pace.op(0)

[FullR]

I find it looks much better to have an empty progress bar initially rather than nothing at all. I'm currently doing an initial render by doing this: pace.op(-1); pace.op();. I would rather just use pace.op(0), but this doesn't work. The count check shouldn't test for a truthy value. Instead, it could just check arguments.length or typeof count === "number".