File tracking.c became rather huge and annoying to maintain and it really contains several independent areas of motrack pipeline. Now we've got: * tracking.c: general-purpose functions which are used by blender, clip editor, RNA and so. * tracking_detect.c: feature detection functions (blender-side, logic is still in libmv). * tracking_plane_tracker.c: blender-side 2D tracking logic. * tracking_plane_tracker.c: plane track tracker. * tracking_solver.c: functions for camera solving. * tracking_stabilize.c: 2D stabilization functions. * tracking_util.c: utility functions for all those files and which shouldn't be public.