Added user.orgs function to get list of user's organizations - #12

gh.user("JangoSteve").organizations( function(data) {
  console.log(data);
});

// =>
{"organizations":[{"gravatar_id":"30f39a09e233e8369dddf6feb4be0308","blog":"http://weblog.rubyonrails.org/","type":"Organization","login":"rails"}]}