* Based on original patch by MattN
* Make stored contacts available as payer data (MattN)
* Add the address-picker element to the dialog for selecting payer details from stored contacts (MattN)
* Add a field-names attribute to the payer address-picker, populated from the request paymentOptions
* Basic CSS to selectively render address fields
* Add mochitests to verify paymentOptions result in the correct payment picker behavior
MozReview-Commit-ID: Br8i5MVyeQ3
4660395f33