Changed searchByLevenshtein function name to dataSearch

... and made it more 'all-round'. Also added contributor to readme.md.

By all-round, I mean: input an existing name, and it will return the Pokémon/Ability/whatsoever.
If you input a misspelled name, it will try to correct it automatically and return the 'right' (according to the levenshtein distance) Pokémon/Ability/etc.