This PR adds a slideshow example (similar to @TodePond's slides but more
on rails) as a way to put some pressure on camera controls.
Along the way, it fixes some issues I found with animations and the new
camera controls.
- forced changes will continue to force through animations
- animations no longer set unnecessary additional listeners
- animations end correctly
- updating camera options does not immediately update the camera (to
allow for animations, etc.)
It also changes the location of the "in front of the canvas" element so
that it is not hidden by the hit test blocking element.
### Change Type
- [x] `sdk` — Changes the tldraw SDK
- [x] `improvement` — Improving existing features
ebc892a1a6