Merge pull request #694 from firebovine/urbandictionary

#  - name : urbandictionary

#    engine        : xpath

#    search_url    : http://www.urbandictionary.com/define.php?term={query}

#    url_xpath     : //div[@class="word"]//a/@href

#    title_xpath   : //div[@class="word"]//a

#    content_xpath : //div[@class="definition"]

#    url_xpath     : //*[@class="word"]/@href

#    title_xpath   : //*[@class="def-header"]

#    content_xpath : //*[@class="meaning"]

#    shortcut : ud

  - name : yahoo