Panning with one finger is disabled even if numInputs is set to two

[pea]

Hey,

Thanks for the library - it's been a life saver.

I've found an issue in which the touch event for one finger is lost when two fingers are being listened to while using the panning event. It seems to be fine until the first interaction and then one finger panning is lost, stopping the user being able to scroll.

Example: https://jsfiddle.net/e7y86aud