Changed
- The `variables_as_json()` function now accepts `include_internal` as
a keyword parameter.
- The `variables_as_json()` function now produces pretty-printed JSON
output.
- Only ordinary users will see flash messages about switching to a
different interview.
Fixed
- Template and static file deletion in Playground.
- Setting the instance name of items that are already in a list.
- Non-mandatory questions were being marked as answered in the
internal dictionary.