Fixed issue with having to restart rails when analytics lib file changed.
Refactored analytics aggregates, easier to understand and to create new aggregates.
Refactored analytics aggregates scoping method, easier and clearer
Refactored analytics aggregate data method to aggregate class method:
* Now easier to create new aggregates
* Moved presentational configuration and data out of the back-end aggregate classes
* Created new analytics data class.
* Made front-end js smarter, able to display multiple value keys for
  each result, don't show legend when no data labels are in results.
Moved application-specific analytics aggregates to app/analytics_aggregates folder.