title: TwitteR setup_twitter_oauth() failing
body: <p>I was following the vignette for the package, updated and loaded all necessary packages, seemed like it would be a pretty straight-forward process to authenticate. Instead, I get an error</p>
  
  <pre><code>&gt; setup_twitter_oauth(consumer_key, consumer_secret, access_token, access_secret)
  [1] "Using direct authentication"
  Error in check_twitter_oauth() : OAuth authentication error:
  This most likely means that you have incorrectly called setup_twitter_oauth()'
  </code></pre>
  
  <p>My paraphrased and redacted program looks more-or-less like this.</p>
  
  <pre><code>library("twitteR")
  download.file(url="http://curl.haxx.se/ca/cacert.pem", destfile="cacert.pem") #read this was necessary for Windows machines
  consumer_key &lt;- 'abc'
  consumer_secret &lt;- 'abc'
  access_token &lt;- '123-abc'
  access_secret &lt;- 'abc'
  setup_twitter_oauth(consumer_key, consumer_secret, access_token, access_secret)
  </code></pre>
  
  <p>I read a lot of the other SO questions on this topic, nothing solved my issue (most of them used the old authentication process anyway). I'm trying to create a wordcloud following <a href="http://davetang.org/muse/2013/04/06/using-the-r_twitter-package/">this tutorial</a>.</p>