add returning out_string support to null server.
add returning out_string support to null server.
Revert "remove warning"

This reverts commit bd14285ea2d0f9e3b9e87a86c24aa3c4e066b9c4.
remove dead code.
add missing validation code in hierdictdoc.
Merge branch '2_10'
changelog update / version bump
move null test inside ModelBase.validate_native
Merge branch '2_10'
add failing tests to http, refactor flat_dict parsing loop code to separate function
docstring updates and other minor changes.
implement own parse_qs that returns None when the string is not given.
fix frequency tests in http
Merge branch '2_10'
add decimal test
changelog update
changelog update
Merge branch '2_10'
fix misc doc errors
Merge branch '2_10'