Spacy-stanza

Fix issue 43: fix alignment when tokenizing with spaCy
Fix issue 47: update dependencies for compatibility with stanza v1.1

* Fix issue 30, 33: Rewrite alignment to preserve whitespace tokens.

* Improve handling of texts with misaligned tokens.
* Add the ability to use `token.feats` as tags.
* Get language attribute directly from Stanza pipeline object.

Thanks to yuhaozhang and SergeyShk for the pull requests.

* Add warning and don't populate `doc.ents` if entities returned by the Stanza NER model don't map to tokens produced by the Stanza tokenizer.

> ⚠️ This release changes the package name from `spacy-stanfordnlp` to `spacy-stanza`.

* Update to [`stanza`](https://stanfordnlp.github.io/stanza/) (formerly `stanfordnlp`).
* Add support for named entities via the `doc.ents` and respective token attributes, if available.
* Rename `StanfordNLPLanguage` to `StanzaLanguage`.
* Change internal language code from `snlp_xx` to `stanza_xx`.

* Fix `stanfordnlp` version pin in `setup.py`.