* in django>=2.1 cmd was removed as parameter to add_parser
* add tox support for django >= 2.1
* introduce helper function to remove cmd paramter form add_parsers when
django >= 2.1
* remove unecessary lines
* fix issues when cmd may be missing in kwargs
* Added failing test for setting a datetime with cli
Issue #186
* Adding myself to AUTHORS
* Handle MultiValueField in manage command, resolves#186
* newline at end
