tools: add a tool to estimate the resolution of a mouse

tools: add a tool to estimate the resolution of a mouse

Relative devices don't provide a physical resolution to the host. For things
like pointer acceleration, the physical amount of movement is better as
baseline than the movement in device units.

Alas, many devices don't come with any information at all, so the users have
to guess. Help that guesswork by providing a tool that does the calculations
for them.

This tool measures the device units covered, then prints the frequency and an
lookup table for various resolutions (in dpi) to match to the physical
movement of the device.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>