Added NFC Attacks

Added a submenu for NFC attacks and functions dumping and writing Mifare cards.
Merge pull request #108 from skysploit/master

Thanks for adding NFC attacks and it looks interesting.  I admit to never using it before and did a little reading: http://robospatula.blogspot.com/2014/02/how-to-clone-mifare-classic-rfid-nfc-cards.html

Have you gotten a chance to test it out?