table.sort() is unstable, meaning that it randomly reorders items with
the same score, so currently fuzzy_find() checks if the line is empty to
not change the original order of the unsorted items. But actually filled
lines have the same problem: e.g. searching foo with filenames like
foo_{1..99}, they are returned in random order.
To fix this sort by score only when 2 items have different score, else
sort by the original position.
Guido Cella
8ae3beeb98