Updated documentation on README

The README requires updates with respect to documentation - initialising models, the loss functions, etc. Expecting an extensive documentation present for each function and class present in the readthedocs documentation. A few things like performance metrics need to be added from the paper as well.

Start by reviewing the README and the existing Read the Docs documentation, then inventory the documented and undocumented functions and classes, including model initialization and loss functions. Consult the paper for the performance metrics to add. Done means the README and Read the Docs documentation comprehensively cover the requested API and paper metrics.

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