xwayland: Use `double` for `xwl_tablet_tool`
So we do not lose subpixel precision in Xwayland.
Suggested-by: Peter Hutterer peter.hutterer@who-t.net Signed-off-by: Olivier Fourdan ofourdan@redhat.com Closes: libinput/libinput#138 (closed)
Edited by Olivier Fourdan