[Feature] An alternative approach to position the `avy-words` based on `eye-focus-distance`.

[sakurawald]

Currently, avy will try to position the avy-words from left to rifht, from top to bottom inside the visible texts of the buffer..

Another possible solution is to sort the candidate words based on the distance from the eye focus (current cursor).

This approach gains:

1. Most jumps are not large jump.
2. For a small distance jump, you get the same/fixed avy-words at the same/similar position.