PN532/NFC routines for AVR-Ada

Supported features:

• SPI and I2C interfaces for PN532
• Read NFC Forum Type 2 tags (NXP Mifare Ultralight, NXP NTAG, etc.)
• Write NFC Forum Type 2 tags
• Read NFC Forum Type 4 tags (NXP Mifare Desfire, etc.)
• Write NFC Forum Type 4 tags
• Emulate NFC Forum Type 4 tag
• Read NXP Mifare Classic tags
• Read Yubikey NEO keys
• Very primitive NDEF parsing included

Not supported:

• Write NXP Mifare Classic tags
• Tag formatting