Add vCard requirement

[cdumez]

We want support for import / export to and from vCard format but do not need to strictly follow the format.

[anssiko]

To clarify, we should mention in the spec that a vCard import/export API is out of scope as parsing and serializing can be efficiently done in JavaScript, and libraries are readily available.

[marcoscaceres]

@anssiko I still think it's on the WG to show that it can be done. I.e., we should at least do some kind of mapping or even make a little JS lib to prove it works.

[efullea]

@anssiko the agreement was to be able to import/export, whereas not being too tied to the vCard format (e.g. attribute names). Keeping the matching of vCard's contact fields with the attributes in the API is thus fundamental.

[marcoscaceres]

Sorry @efullea, I'm having trouble understanding what you mean by "Keeping the matching of vCard's contact fields with the attributes in the API is thus fundamental." Can you give an example?