Returns the Levenshtein distance between two sequences. May either be passed
the two sequences or a diff of the two sequences.
The Levenshtein distance between two strings is the minimum number of edits
needed to transform one string into the other, with the allowable edit
operations being insertion, deletion and substitution of a single character.
This function works not only with strings but with any Clojure sequence.
Warning! Technically this function is estimating the Levenshtein distance
from a computed diff. Most of the time, it is the same as the real Levenshtein
distance but in same cases it may be larger. The reason for this is that
there may be multiple paths through an edit graph with the same edit
distance but with differing Levenshtein distance. A future improvement to
the diff algorithm whould be to find all paths and prefer the one with the
minimum Levenshtein distance.