- Rename the nfc_device_t's struct iErrorCode member to iPICCError (We are
likely to have both PICC and PCD errors fields to avoid unneeded complexity
at some point);
- Make the PN53x error descriptions static;
- Enhance some comments here and there.
Avoid redundant code in PN53x usb and uart drivers. Since it makes sense to
report errors at the nfc_device_t level, pass it directly to
pn53x_transceive().
Programs using the libnfc MAY use pn53x_transceive() to communicate with a NFC
device, and SHALL not use anymore pnd->pdc->transceive(). Code in the library
itself SHOULD avoid calling pnd->pdc->transceive(), so such construct have been
updated accordingly.
- New API functions: nfc_strerror(), nfc_strerror_r() and nfc_perror();
- Drivers now have a reference to chips callback methods;
- Rename -pn53x_err2string to pn53x_strerror and add it to pn53x_callbacks_list.
