Suggestion: pad range should be configurable

[djipco]

I hope you don't mind my suggestions but I like your library and care to make it better.

It would be nice if the pad's range was configurable. For instance, I currently need to use it to pick a position on screen. Therefore, if I was to set the horizontal range to 0-width and the vertical range to 0-height, it would be very convenient.

Also, I see that you have elected to use an array for the x and y but it might be nice to have the option to use an object instead: {x: 0, y:0}.

Thanks.

[automat]

relevant #15