3.6.0 - `unpack_fixtures` in classes + `current_cases` improvements

• The current_cases fixture now contains case parameters if any. Fixes #214

• The current_cases fixture entries are now instances of namedtuple.

• New in_cls argument in unpack_fixtures so that it can be used inside classes. Fixes #201

• Fixed minor issue where empty entries could be present in currentcases. Fixes #213

See documentation page for details.