text: Title: Pluralization gives dubious results on some corner cases
  Body: Hi,
  Thanks for providing and maintaining this library.
  
  I noticed that some corner cases are not handled properly.
  Notably:
  `
  from textblob import Word
  print(Word("lynx").pluralize())     # prints "lynges"
  print(Word("jeans").pluralize())     # prints "jeanss"
  `
  I'm not a native speaker but I can't find any mention of "lynges" in any dictionary, so I assume it's wrong. The merriam-webster suggests "lynxes".
  The double s problem is self explanatory.