Release 4.1.0 (plotly#1704)

* Added 4.1 CHANGELOG
* Update README installation instructions
* Bump versions of plotlywidget and jupyterlab-plotly to 1.1.0
* Remove px __version__ var now that px is integrated into plotly.py
* Fix facet row label ordering
* Fix row_titles to honor start_cell specification

Release 4.1.0 (plotly#1704)

* Added 4.1 CHANGELOG
* Update README installation instructions
* Bump versions of plotlywidget and jupyterlab-plotly to 1.1.0
* Remove px __version__ var now that px is integrated into plotly.py
* Fix facet row label ordering
* Fix row_titles to honor start_cell specification

Release 4.1.0 (plotly#1704)

* Added 4.1 CHANGELOG
* Update README installation instructions
* Bump versions of plotlywidget and jupyterlab-plotly to 1.1.0
* Remove px __version__ var now that px is integrated into plotly.py
* Fix facet row label ordering
* Fix row_titles to honor start_cell specification

Fix plotly express marginals

Go back to start_cell bottom-left since that makes marginal code easier.
Now flip the row index of traces before they are inserted in the grid.

Finalize README versions

Bump versions of plotlywidget and jupyterlab-plotly to 1.1.0-rc.1

Bump versions of plotlywidget and jupyterlab-plotly to 1.1.0-rc.1

Bump versions of plotlywidget and jupyterlab-plotly to 1.1.0-rc.1

Merge pull request plotly#1666 from plotly/v4_integration

Version 4 integration

Merge pull request plotly#1666 from plotly/v4_integration

Version 4 integration