Refactored methods to view different lists.
Added tests for POST requests for tasks.
Fix to set current (and done) on new tasks and to save is_routine field for tasks.
"Add" link in UI now displays a form to create a new to do with options
to set it as a one-time or routine task for now or later.
Initial list of current tasks now properly updates on refresh after
adding a new current task. Used to process the queryset only once.
Todo form can be closed and shows errors. Also adds newly created todos to
the current list (temporary behavior; will change later).