Use ts_setup() to match default tslib search behavior

The tslib handler checks the TSLIB_TSDEVICE environment variable and then falls back to /dev/input/event1. Tslib itself does a few other things, e.g. checking for /dev/input/touchscreen. So if one does not specify the environment variable it can easily happen that things work in tslib (e.g. ts_calibrate), but not with Qt.

Is there any reason not to use ts_setup(), which does all this, and afterwards print out which device is used? This function also looks into the same environment variable first, and scans input devices if no default path matches, so it should not cause great surprises.

Is there any reason not to go this route? Otherwise I can cook up a patch.