New metric calculation mechanism

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

Updated feature set for segmentation and classification

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

Major refactor finished

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

Final tag before major refactor

0.0.8

Merge pull request #39 from sarthakpati/master