iAbortFd file descriptor array have been removed from nfc_device_t;
nfc_abort_command() can now failed (return false);
nfc_abort_command() now call abort_command pointer from drivers;
pn532_uart and arygon drivers use a pipe-based mecanism (similar from previous one);
pn53x_usb driver use a boolean flag-based mecanism (the previous one does not work as expected);
pn53x_usb now print smarter messages on error at usb connection;
pn53x_usb now handle a strange case: sometimes, the first sent command is not ACKed by PN53x USB device, a dummy command is now sent.