Simple Arygon NFC reader interface

Example:

# erl -s arygon_nfc -arygon_nfc device \"/dev/tty.SLAB_USBtoUART\"

Will start application with the device set in application environment To get nfc events the user then subscribes to those.

1> arygon_nfc:subscribe().
   {ok,#Ref<0.0.0.1483>}

2> flush().
   Shell got {nfc,#Ref<0.0.0.1649>,device_open}

3> arygon_nfc:command("0p").
ok

Someone swipe a NFC card

4> flush().
Shell got {nfc,#Ref<0.0.0.1483>,{select,"044D9D6A252680"}}
ok

Read the arygon_nfc:client() code to see a state machine in action