Adds delegate methods that enable a workflow to enter & confirm a new PIN

Hi Thomas,
I added two delegate methods that allowed me to keep the pin view controller open. I wanted that for the workflow of entering a new PIN and then have the user confirm it without having the pin view controller disappearing between the two steps.

I am not sure if this fits with the direction you would like take your controller, but here it is in case you find it useful.

Thanks,
nils