removed unnecessary import of codecs, cf https://github.com/robwahl/nltk/commit/13815be63d6243308d585245bd5041d56ed460e7
removed unnecessary import of codecs, cf https://github.com/robwahl/nltk/commit/13815be63d6243308d585245bd5041d56ed460e7

nltk/nltk,nltk/nltk,nltk/nltk