* [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