- make sure "fit.config_fits" is only accessed for MultiFits objects - make sure auxdata is a pandas DataFrame in `export_data()` - fix concatenation not performed over the index-dim in `export_data()`
- make sure "fit.config_fits" is only accessed for MultiFits objects
- make sure auxdata is a pandas DataFrame in `export_data()`
- fix concatenation not performed over the index-dim in `export_data()`

TUW-GEO/rt1