ntag2xx_ReadPage only reads 4 bytes at a time

[scottjenson]

Adafruit_PN532.cpp specifically calls out in the code that it limits reads 4 bytes at a time:

/* Copy the 4 data bytes to the output buffer         */
/* Block content starts at byte 9 of a valid response */
/* Note that the command actually reads 16 byte or 4  */
/* pages at a time ... we simply discard the last 12  */
/* bytes                                              */

For the more modern tags (I'm using NTAG213) you can read 16 bytes at time. I don't understand the spec well enough to know if there is any way to test for this 4/16 split. However if I change the following line
memcpy (buffer, pn532_packetbuffer+8, 4);
to
memcpy (buffer, pn532_packetbuffer+8, 16);
It works great for my tag (and I'm running 4x faster)

One alternative would be to pass in a flag to ntag2xx_ReadPage so you could just specify reads of 4 or 16 bytes.