Animate cursor bullet overlay

[raineorshine]

Steps to Reproduce

- a
- b
- c

Move the cursor from a to b.

Current Behavior

The cursor bullet overlay (the gray circle around the cursor bullet) immediately snaps to b.

Expected Behavior

The cursor overlay bullet should smoothly animate to its new location with veryFastDuration and ease-in-out.

I recommend rendering the cursor bullet overlay with position: absolute in the LayoutTree next to the TreeNodes, since the LayoutTree has the thought positions.

The overlay must be perfectly centered on the bullet:

• at all font sizes
• on all platforms
• table view

When the cursor thought moves (e.g. indent, moveThoughtDown), the overlay should track with the bullet like it does currently.