- Improve tooltips a lot:
    - They now never get cut off by the edge of the screen
    - They never overlap the hovered option/group/category
    - They don't take half a second to appear
    - They don't disappear when you move your mouse
- `ButtonOption` now consumes itself, so you can access it when building.
- Make `Option#available` mutable with `Option#setAvailable`