title: Configure Travis CI run exactly the same checks as check --as-cran?
body: <p>Is there a way to get Travis CI to perform exactly the same checks as</p>
  <pre><code>R CMD check --as-cran
  </code></pre>
  <p>?</p>
  <p>Currently my check passes <code>--as-cran</code> locally with 0 errors and 0 warnings. But I see lots of warnings via Travis CI which don't occur during CRAN checks.</p>
  <p>Here is a sample or the warnings Travis CI generates (that CRAN checks don't):</p>
  <pre><code>Package hyperref Warning: Option `hyperindex' has already been used,
  (hyperref)                setting the option has no effect on input line 377.
  
  </code></pre>
  <pre><code>Package rerunfilecheck Warning: File `Rd2.out' has changed.
  (rerunfilecheck)                Rerun to get outlines right
  (rerunfilecheck)                or use package `bookmark'.
  </code></pre>
  <pre><code>LaTeX Font Warning: Font shape `T1/zi4/m/it' undefined
  (Font)              using `T1/zi4/m/n' instead on input line 43.
  </code></pre>
  <p>One way around this is to configure Travis CI to stop treating warnings as errors, but I prefer it fail on warnings, but only on warnings CRAN would also elicit.</p>