NFC vCard

I'll open a pull request for NFCTag.js on the weekend.

About downloading arbitrary data using NFC:
It's generic and works for text, images, js... for this reason the data is wrapped in a NDEF MIME Record. Andoird features an API for wrap und unwrap.

Wrap and unwrap is missing from Pucks JS-Engine, namely:

• Parse and skip NDEF Message Header. (Usually 2 or 4 bytes)
  
• Parse and skip NDEF MIME-Record Header. (Here length greatly depends on the payload type string e.g. "text/javascript" is already 15 bytes on it's own.)
  
  

If there is interest I would invest some time into a MIME record wrap unwrap module.