refactor voter::courseload() to return a result specific to the input election
removing unused fn; we are not going to enforce this constraint
relax validation on election start times
make use of excluded curric codes for determining eligibility
cleanup the top of ballot.php. Create logical, Moodle-y groupings of boilerplate. rename 'candoanything'. Remove redundant data in customdata. Refactor metadata check method to return useful info on failure