Added CSV Export

This morning I committed a bunch of changes which allow the roster to be exported in CSV format.  The CSV format can be opened in Excel or other tools which can deal with comma separated data.  We’re using the data to order t-shirts and verify that all of the families of the swimmers on the roster have been billed correctly.  Now that the CSV export is working correctly, I will go back and modify the SDIF export so it sends a file download to the browser as opposed to having to copy and paste it like it currently is.