Auto-depth is no longer reset during consecutive touch-pad motion. Details: - Add wmEvent::flag, WM_EVENT_IS_CONSECUTIVE to detect consecutive track-pad & NDOF motion events. Expose via RNA as Event.is_consecutive. - Consecutive events are broken by button/key presses and mouse motion. - Add `WM_event_consecutive_data_*` functions, so operators can store data between consecutive events. - Add `ED_view3d_autodist_last_*` functions to access the last autodist pivot point for view operators to use.