low layer using PN532 instread of Adafrit_NFCShield_I2C
update with PN532 library
Merge branch 'dev' of https://github.com/xiongyihui/Ndef into xiongyihui-dev

Conflicts:
	MifareClassic.h
mix method missed in merge
Merge branch 'xiongyihui-dev'

Fixes #12