title: could not find function "cast" despite reshape2 installed and loaded
body: <p>In following Hadley Wickham's <a href="http://had.co.nz/thesis/">"Practical tools for exploring data and models"</a> examples in section 2.4, <em>Casting molten data</em> I'm getting <code>Error: could not find function "cast"</code>. I have the reshape2 package installed and loaded. </p>
  
  <pre><code>&gt; cast(msmithsm, time + subject ~ variable)
  Error: could not find function "cast"
  </code></pre>