Function Levenshtein

Levenshtein(str, cmp): number
Calculates the Levenshtein distance of two strings. This function is better than most because it takes utf8 characters into account.

More information on it can be seen here, on wikipedia.
Parameters
- str: string
  The string
- cmp: string
  The string to compare to
Returns number
A "distance" number - the higher, the further str is from cmp