title: dygraphs, Exclude NAN NULL values from rolling average
body: <p>With dyGraph, when a value in set to NAN or NULL the value is not plotted.  However, if the roll value is set to a number greater than 1 the gaps begin to get smaller.  Basically the NULL/NAN is somehow used in the rolling average.  For example, if there are five time periods without data the and the roll value is 10 the spaces doesn't show up. A roll value of 2 leaves a 3 period gap.</p>
  
  <p>Is there any way to always make sure the data gaps remain the proper length?</p>
  
  <p>Thanks for your time.</p>