working out how to get non-payers accounted for
update list of changed cards on file; create list of invalid stage histories to be ignored; add 'Paying' funnel stage.
fix bug in date parsing effecting minutes (was always '4' before); clean out logging; set up for handling muleiple classes; remove invoice handling; treat payers as having their own potentials
show course checkboxes (though not yet in effect); clean up comments; show course in student details table
clean up hadnling of out of order stage histories (using new values in Constants.js); fix bug in time zone handling for 'Signed up at'; beginnings of handling multiple courses
remove querying of stripe for invoices. not necessary