title: How to get rrule.between() to only include start timestamp
body: <p>How would I create an rrule that excludes only the end timestamp using dateutil? Would I have to create a custom function or is there a way to do it natively?</p>
  
  <p>here is an example</p>
  
  <pre><code>rule = rrule.rrule(rule.HOURLY,tsstart=somedate,until=somedate_four_hours_later)
  </code></pre>
  
  <p>I want the output to EXCLUDE <code>somedate_four_hours_later</code> and only generate 4 timestamps, somedate, somedate+1 hour, etc.</p>