Dates added to Seasonal Analysis topic

New week modes that label explicit dates have been added to the Seasonal Analysis topic.  Previously, the data were listed with just week numbers (with optional years), but now an approximated date for the end of the week (e.g. ‘Apr 20’) can be selected, or the same can be presented in YYYY-MM-DD format (e.g. ‘2015-04-20’).  The week ending dates are fixed based on week number across all years (therefore, we call them approximated), because weeks can shift a little across years and we still need the data to join across years.  However, users may find the more explicit dates more useful than the week of year numbers.  To select the modes, use the Week Mode dropdown.