removed _lcs_by_depth(), see https://github.com/nltk/nltk/pull/662
fixed some wordnet omw doctest bugs
formatting
restricted matching of wordnet tab files so the non-data ones are ignored; added "fra" to wn.langs() doctest
added file encoding
python 2.6 compatibility doctest fixes
Merge pull request #669 from jskda/pull_request.505

Fixes to omw wordnet