Support horizontal/vertical fraction for auto_zoom_on_focus (#173)

Co-authored-by: Rafał Chłodnicki <[email protected]>

Add .python-version to support newest ST4 (#174)

Fix fallback logic for view settings (#166)

remove type annotation

fix some minor style issues

Automatically Cull Empty Panes When Traveling Away (#150)

* Added option to automatically cull empty panes when moving away from them (configured via "destroy_empty_panes", defaults to False)
* simplified has_content logic into in-place check for any open views
* update `window.get_layout()` to newer `window.layout()`

Add some extra cases to satisfy type-checking

Remove unneeded changelog message

Only close the current pane if a window isn't closing

Fixes #149