Simply prints the various events to make it easier to check what's coming out
of libinput. Works for --udev (the default) or for --device /dev/input/event0.
Example output:

event7 	DEVICE_ADDED	seat0	default
event8 	DEVICE_ADDED	seat0	default
event4 	POINTER_BUTTON	 +1.35s	272 pressed
event5 	POINTER_MOTION	 +2.31s	 -3.00/  2.00

Time is displayed relative to the starting time.

Note: statically linked for easier debugging, but we don't distribute it
(yet) anyway.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Jonas Ådahl <jadahl@gmail.com>