input: Store touch position and time when we start an implicit touch grab
input: Store touch position and time when we start an implicit touch grab

sir-murray/weston,mchalupa/weston,giucam/weston,udoprog/weston,xorgy/weston,krezovic/weston,Gnurou/weston,sir-murray/weston,Fantu/compositor-spice,jonnylamb/weston,giucam/weston,jonnylamb/weston,eyolfson/weston,eyolfson/weston,kwm81/weston,kwm81/weston,krezovic/weston,mchalupa/weston,Gnurou/weston,Tarnyko/weston-xdg_surface_present,Tarnyko/weston-xdg_surface_present,Fantu/compositor-spice,Fantu/compositor-spice,xorgy/weston,udoprog/weston