Add new output mode to create udev-rule for libinput

The new mode allows to write the udev rule directly, so later no access
to the binary or pointercal is needed. This speeds up the udev execution
time and allows a cleaner startup of weston.
The rule assignes the calibration of /etc/pointercal to all detected
touches as LIBINPUT_CALIBRATION_MATRIX, which was done on the fly
before.

output: Allow special value 'stdout' for -o, add quiet param, add some output.

Some cases have a filename as default when -o/--outputfile is not set.
Here -o stdout can now be used to print to stdout instead.

Also adds some informativ output and a -q/--quiet parameter to suppress
it.

fix: Fix wrong free() call when outputfile don't contains dir part.

The pointer returned from dirname are not supposed to be passed to free,
as it may also contain statically allocated strings. Keep the pointer
returned from strdup and free that instead.