moj_date_fieldset

 - replace date drop down boxes with moj_date_fieldset (three text boxes), 
 - implement JS code to handle showing / hiding based on dates in text boxes rather than drop downs,
 - change tests to fill in date text boxes rather than date_select
 - change JS to always submit month as zero-filled numeric string so that Capybara version of JS new Date works
- implement date range validation