Elephas

- Fix bug in installation on Windows (https://github.com/danielenricocahall/elephas/issues/19)

- Fix typo in `setup.py` (`iinstall_requires` -> `install_requires`)
- Copy `README.md` to serve as documentation in PyPI (https://pypi.org/project/elephas/3.4.6/)

- Remove usage of `requirements.txt` in `setup.py`, which caused installation failures (https://github.com/danielenricocahall/elephas/issues/17) when installin 3.4.2

- Remove references to `SQLContext` as that was deprecated in Spark 3.0
- Change `lr` to `learning_rate` in all `SGD` arguments
- Pin the Tensorflow version to <=2.10, as 2.11 results in `weakref` errors in serialization (https://github.com/danielenricocahall/elephas/issues/16)
- Enhance typehints and docstrings

- Addressed bug with `MulticlassMetrics` mentioned in example (https://github.com/danielenricocahall/elephas/issues/4)

- Enable saving and loading models from network accessible Hadoop cluster (https://github.com/danielenricocahall/elephas/pull/5)