title: Look for consecutive rows based on Hour and grouped by Date
body: <p>I currently have a table with hour and dates. I'm trying to look for consecutive hours per date where the 'cnt' column is not equal to 0</p>
  
  <p>For this data:</p>
  
  <pre><code> Date       Hour V1 V2 Cnt
   ---------------------------
   2015-12-15  1   a  b   1
   2015-12-15  2   a  b   2
   2015-12-15  2   b  b   2
   2015-12-15  3   a  b   3
   2015-12-15  3   b  b   2
   2015-12-15  4   a  b   0
   2015-12-15  5   a  b   1
   2015-12-15  6   a  b   1
  </code></pre>
  
  <p>Based on the table above, Date 2015-12-15 has 2 instances where there are consecutive hours where cnt is not equal to 0 (1-3, 5-6)</p>
  
  <p><em>Duplicate hours could only happen if V1 and V2 are different</em></p>
  
  <p>I'd like to reach this output:</p>
  
  <pre><code> Date       Hour V1 V2 Cnt Cons
   ------------------------------
   2015-12-15  1   a  b   1   3
   2015-12-15  2   a  b   2   3
   2015-12-15  2   b  b   2   1
   2015-12-15  3   a  b   3   3
   2015-12-15  3   b  b   2   1
   2015-12-15  4   a  b   0   0
   2015-12-15  5   a  b   1   2
   2015-12-15  6   a  b   1   2
  </code></pre>