* [WIP] add date/time question type
* Date/time questions python classes, types and form handling
* use own timepicker
* Fix argument naming
* Add css and js for datetimepickers
* remove not needed str call
* seperate splitdatetime widget template and fix date/time questions
* change date placeholder to dec 31
* do not show seconds in presale time pickers
* improve codestyle
* add new question types to api doc
* add test
* expand test to datetime question
* add new questiontypes to changelog
remove duplicate parens
* remove timezone from time only question answers
* improve codestyle
* Fix date and time formatting in control question overview
* Checking for the last date in the event series before deleting a date. Last date in a event series should never be delted.
* Adding check to ensure that last date in a event series is not deleted. Editing unit test around deleting subevent to assert on alert-danger
* Increasing the scope of test_delete. We are now creating 2 subevents and testing deleting one and ensuring that the last one is not deleted
* Fixing alert text. Removing a redundant if condition for checking subevent count
* Adding assert for second event to ensure its not deleted
* Minor fixes and rebase
When using the test data generation script, the demo conference no longer has the URL ``/bigevents/2018``, but is now moved to ``/bigevents/2019`` . This confused me in the beginning.
* standardize use of check-in
* split on occurrence of "checkin_*"
Instead of skipping when encountering "checkin_*", we now split and only
pass the second part to the spell-checker. This fixes the aforementioned
problem.
* fix spelling issue with checkins
