Aqdefreader

- Added support for empty fields in the measurements.
- In `create_column_dataframe` it is now possible to specify if the resulting DataFrame shall be grouped by date or not. Default behavior is grouping as before but if e.g. not date and time is available in the measurements, grouping can be disabled by `group_by_date=False`.

fixed errors with files including settings valid for all characteristics (set with xxx/0)

**Full Changelog**: https://github.com/successfactory/aqdef-reader/compare/1.1.0...v1.1.2