Following D1894, we have a convenient way to update our speed. We can use this to make unitMotion call VisualActor directly, instead of the reverse. This lets us clean up code in unitAI.
To let unitAI overwrite our idle/walk animations, we only replace the 'idle';'walk';'run' animations. Note that using animation variants, this means we support doing things while walking, to an extent.
Not subscribing to MT_Update in VisualActor is a performance improvement of several µs per turn based on past profiling of messages.