Separate wiktionary gem

It seems now with Infoboxer we can do incredibly useful Wiktionary client. Wiktionary contents is much more regular than Wikipedia's, so there can be plenty of:

``` ruby
word = Wiktionary['dog']
word.noun.plural # => dogs
word.synonyms
word.noun.meaning
word.translations
```

And so on. Not very easy, not very hard, extremely useful.
