break condition ACR122_USB::targetPresent gets lost somewhere.

[tobias-strenger]

I will probably fix this myself. Just in case you have some ideas.
In ACR122_USB::process():

while (ACR122_USB::targetPresent) {
        libusb_handle_events_timeout (usbContext, &t);  // zero timeval = return immediately (non blocking)
        usleep(100000);
}

This loop doesnt break in some cases even if the target was removed. The signal lamp on the device however, indicates, that the device itself recognize it correctly if the target was removed.

It can be reproduced by putting the target just for a short time on the device, or not even touch the device. It happens regularely.