* Add stub files for main API classes
* Add contributor agreement for ezorita
* Update types for ndarray and hash()
* Fix __getitem__ and __iter__
* Add attributes of Doc and Token classes
* Overload type hints for Span.__getitem__
* Fix type hint overload for Span.__getitem__
Co-authored-by: Luca Dorigo <dorigoluca@gmail.com>
