Necessary bug fixes and logging improvements

In this version we provide necessary bugfixes for v0.1.1 and several improvements:

Big changes

• Bugfixes in FastMRI dataset class.
• Improvements in logging.
• Improvements by adding more exceptions for unexpected occurrences.
• Allow the reading of subsets of the dataset by providing lists.
• Add an augmentation to pad coils (zero-padding), allowing the batching of images with a different number of coils.
• Add the ability to add additional models to the engine class by configuration (WIP).

Stylistic changes

Black is now used as a code formatter, this had the consequence that certain parts became hard to read, so these were refactored to improve readability after applying black.

Breaking changes

As you can expect from a pre-release, while we intend to keep it to a minimum, it is possible that things break, especially in the configuration files. In case you encounter one, please open an issue.