- Replace OpenCV with imageio
- Add (ancilliary) computation of volume (11)
- Add convenience methods for `Configuration`
- Refactoring (8):
- Separate classes for .tdms, dict-based, and hierarchy datasets
- Introduce "_events" attribute for stored data
- Data columns (including image, trace, contour) are accessed via
keys instead of attributes.
- Make space for new hdf5-based file format
- Introduce ancilliary columns that are computed on-the-fly
(new "_ancilliaries" attribute and "ancilliary_columns.py")