Napari-workflow-inspector

New features
* Undo/redo history panel

Bugfix
* Do not set matplotlib backend globally (Thanks to Cryaaa )

New features
* Changed graph visualization backend to networkx (big thanks to jo-mueller )
* Color scheme: magenta instead of red

Removed features
* Code generation (use napari-script-editor instead)

Changes
* Use napari-workflows instead of napari-time-slicer as workflow infrastructure has moved there

Under the hood changes only: Moved the code generator to napari-time-slicer

New features
* Generated code is processed by autopep8 to improve code quality

Bug fixes
* Image data flow graphs are updated also if just names changed
* White box was removed from empty widget layout