- 
            Breaking change*: Optional parser no longer unflattens sequence, parsers
            like int_ >>
            -(int_
            >> int_)intotuple<int, optional<int>, optional<int>>will produce a compilation error
            in sequence parser. This was a bugfeature which might be reimplemented
            in the future.
- 
            Fixed list parser with attribute-less subject in sequence parser. GH#663
          
- 
            Fixed optional parser with container attribute in sequence parser. GH#665
          
- 
            Fixed error_handlernewline/whitespace
            handling issues. GH#669 GH#670
- 
            Fixed seek[...]directive going past the end of input introduced in GH#30, triggered when
            pre-skip leaves no data. GH#658 GH#683
- 
            Removed rollback in rules to fix a regression introduced in GH#670. GH#686