Docstrings and method signatures

[JonTong]

When running in Jupyter or ipython, attempting to bring up the documentation for the iForest class produces only:

Init signature: iso.iForest(self, /, *args, **kwargs)
Docstring:      <no docstring>

While the example notebooks provide sufficient guidance on how to use the iForest class, it would be useful to have this available at the point of usage - both the full argument specification and the docstrings.

This might just be a question of setting the binding compile option of Cython to true (e.g. via decorators @cython.binding(True).

Happy to help out and create a PR if this would be desired/useful.