Branches/fix losing punches bug

I've discovered a bug wherein some of the punches (particularly the most recent punches) were being lost during the combination.  I tracked it down to the rake task, mostly.  There was an issue where the punch has been changed in the model code (making it into a combo) but the original record was being used numerous times, causing the hits not to accumulate properly.  It was a bit tough to track down and I only sort of grok what was happening.

This code resolves this issue.  On heavily trafficked days we were losing quite a number of impressions.  Luckily it was noticed by some of our contributors that their impression counts were suddenly dropping at some point.
I was finding there were sometimes multiple, overlapping combo records for a single time period.  The prior code would not let them combine into each other.  This allows the multiple combo records for a given timeframe to combine into a single entity.