Rotary dialer emits two `dial` events per digit

[urish]

You can see the issue in this GIF:

One event is emitted when the target digit hits the finger stop, and another one when the dialing animation finishes.

I suggest to change the behavior as follows:

• emit a dial event when the digit hits the finger stop (as it does now)
• emit a dial-end event when the animation finishes
• optionally emit a new dial-start event when dialing animation start

This way, it would be analogous to keyboard/mouseevent, where you have a triplet of keydown/keypress/keyup or mousedown/click/mouseup events.

[LironHazan]

@urish can you assign to me? :)