Cleanup

[Nicholas-Schaub]

This PR cleans up the code base a little bit. No major changes were made to the code.

The primary edits were:

1. Minor changes to documentation formatting
2. Changes to log levels for better verbosity level control (to be implemented in next PR)
3. A change in how the BaSiCPy class is initialized for better type hints when coding. We originally overrode __init__ and used **kwargs to handle input arguments. This makes for messier type hints in code editors.

[yfukai]

This closes #102.

[yfukai]

I added the warning after the loop to deal with cases in which all the iterations do not converge but the reweighting iteration converges. Feel free to revert it if you find it not good.