title: Rolling windows with column based condition?
body: <p>How could I join the rows based on the <strong>resume</strong> column?<br />
  I mean, go joining the rows until in <strong>resume</strong> column there is a <strong>1</strong>.<br />
  For joined rows I want to use an aggregate function for each column, something like that:</p>
  <pre><code>{ 'tunein': 'first', 'tuneout': 'last', 'watching(minute)': 'sum' }
  </code></pre>
  <p>Example: from this dataframe</p>
  <pre><code>  account_id    asset_id     tunein      tuneout resume watching(minute)
  1   61745         2967      12:42:00    13:01:00    0   19.0
  2   61745         2967      15:48:00    15:51:00    1   3.0
  3   61745         2967      15:52:00    15:56:00    1   4.0
  4   61745         2967      15:57:00    16:23:00    0   26.0
  5   61745         2967      21:06:00    21:10:00    0   4.0
  6   61745         2967      22:17:00    22:37:00    1   20.0
  7   61745         2967      23:55:00    23:58:00    1   3.0
  </code></pre>
  <p>get this:</p>
  <pre><code>  account_id    asset_id     tunein      tuneout resume watching(minute)
  1   61745         2967      12:42:00    15:56:00    0   26.0
  2   61745         2967      15:57:00    16:23:00    0   26.0
  3   61745         2967      21:06:00    23:58:00    0   27.0
  </code></pre>