Gandlf

Changelog:

- Misc bugfixes for segmentation and classification
- DFU 2021 parameter file added
- Added SDNet for supervised learning - https://doi.org/10.1016/j.media.2019.101535
- Added option to re-orient all images to canonical
- Preprocessing and augmentation made into separate submodules

Changelog:

- Half-time epoch loss and metric output added for increased information
- Gradient clipping added
- Per-epoch details in validation output added
- Different types of normalization layer options added
- Hausdorff as a validation metric has been added
- New option to save preprocessed data before the training starts

- First level of code re-organization
- No API changes for config files