Walk Navigation was missing rotation keyframes on confirm (when animation
wasnt playing) after rB22bdd08dfd0.
Because for walk [in contrast to fly], the cursor is constantly warped
(WM_cursor_warp in walkEvent), we cant do something reasonable with
comparing mouse positions (to detect rotation) when mouse comes to rest.
Now remember if rotation changed at any time.
Also tweaked the insertion for location keyframes (which was always
happening even if the camera did not move), now checking the real dvec
(instead on relying on speed)