Adding Mifare Ultralight support to librfid

Since (as opposed to MiFARE Classic) the Philips proprietary MiFARE Ultralight RFID Transponder is actually documented quite well, I've added support for it to librfid. In theory it should work (I've implemented it just like the data sheet says), but unfortunately the transponder doesn't reply to READ/WRITE commands yet :(

The reason for implementing MiFARE ultralight is mainly to have a closer look at the Champions League Tickets from last year, since they are the "beta test" for the Soccer World Championship here in Germany next year.