HydraFW HydraNFC/TRF7970A Tutorial added for HydraBus/HydraNFC and latest firmware (at least version HydraFW_v0.4-beta-56-g09d47ac see release).

See https://github.com/bvernoux/hydrafw/wiki/HydraFW-HydraNFC-TRF7970A-Tutorial

The tutorial details how to:

• Initialize GPIO & SPI to communicate with TRF7970A/HydraNFC
• Initialize & read ISO15693/Vicinity Tag
• Initialize & read ISO14443A/Mifare Tag
• Use TRF7970A commands (SLOS743K – August 2011 – revised April 2014)