title: roxygen2 not fully updating DESCRIPTION file
body: <p>I'm making my first package <code>rlandscape</code>, using Roxygen2 and trying to follow the plain  Roxygen vignette since Roxygen2 doesn't have one.</p>
  
  <p>As in <a href="http://cran.r-project.org/web/packages/roxygen/vignettes/roxygen.pdf">the vignette</a> (page 3), I created a file called <code>rlandscape-package.R</code> that contains nothing but package documentation. In the vignette, they say</p>
  
  <blockquote>
    <p>each Roxygen description block must be followed by a statement, even
    header material that describes a le or package in lieu of a specific
    function. roxygen() is provided as a NOOP (null statement) to stand in
    for such cases.</p>
  </blockquote>
  
  <p>but if I follow the description block with <code>roxygen()</code> a call to <code>package.skeleton</code> produces <code>Error in eval(expr, envir, enclos) : could not find function "roxygen"</code>. So I've tried leaving the <code>roxygen()</code> call out entirely as well as replacing it with <code>NA</code>, both of which seem to produce the same results: <code>package.skeleton()</code> works successfully (including <code>rlandscape-package.R</code> as one of the <code>code_files</code> arguments), and I can then <code>roxygenize</code></p>
  
  <pre><code>&gt; roxygenize("rlandscape", roxygen.dir = "rlandscape")
  Updating collate directive in  /Users/Gregor/Dropbox/rlandscape/rlandscape/DESCRIPTION 
  Updating namespace directives
  Writing plot.landscape.Rd
  Writing rland.Rd
  Writing rland.gui.Rd
  Writing makePoints.Rd
  Writing rCluster.Rd
  Writing rlandscape-package.Rd
  Writing rlandscape.Rd
  </code></pre>
  
  <p>which seems to run successfully, but the DESCRIPTION file has the "Collate" field appended, but is otherwise unchanged from what <code>package.skeleton</code> created. Why isn't the rest of the description file updated?</p>