title: pandas Series to Dataframe using Series indexes as columns
body: <p>I have a Series, like this:</p>
  <pre><code>series = pd.Series({'a': 1, 'b': 2, 'c': 3})
  </code></pre>
  <p>I want to convert it to a dataframe like this:</p>
  <pre><code>    a   b   c
  0   1   2   3
  </code></pre>
  <p><code>pd.Series.to_frame()</code> doesn't work, it got result like,</p>
  <pre><code>    0
  a   1
  b   2
  c   3
  </code></pre>
  <p>How can I construct a DataFrame from Series, with index of Series as columns?</p>