I think that this API is not intuitive.

Now `fromX` is `fromX` times `tile` in the x axis, `y` is `y` times `tileh` and `toX` is used as the limit in the x axis.
Moreover if you set a value for `toX` that is less than `fromX` the sprite is used contrariwise.

In my opinion it would be better to pass only a `reelId`, a `duration`, a `numberOfFrames`.
I would like also an optional parameter `tileSize` of type `Object` that should contain a specific tile size for the reel in the form `{w: Number, h: Number}`.

I think also that the version with the array of positions is useless.