Version 3.0.0-alpha.0 - The major revamp 🌈

Summary

• Gestures and Event Controllers are used for tools @amolenaar (#159)
• Simplifications in aspects.
• gaphas.View and gaphas.GtkView are merged into gaphas.view.GtkView
• Prototypes for Canvas and Item
• Introduced type checking with MyPy

🧰 Changes

• Fix build and consolidate build steps @amolenaar (#160)
• Split aspects module in to a package of multiple modules @amolenaar (#157)
• Improve type hints @amolenaar (#152)
• Item constraint handling @amolenaar (#145)
• Merge view @amolenaar (#144)
• Painters without view @amolenaar (#143)
• Fix doctests @amolenaar (#122)
• Painter package @amolenaar (#139)
• Move logic out of canvas @amolenaar (#138)
• Rename solvable to variable @amolenaar (#137)
• Separate view selection @amolenaar (#136)
• Update projections @amolenaar (#129)
• Remove cache variables @amolenaar (#126)
• Remove pickle related code @amolenaar (#118)
• Add type information @amolenaar (#120)
• Enable docformatter pre-commit hook @danyeaw (#102)
• Enable Pre-commit Hooks for mypy, isort, toml, yaml, and flake8 @danyeaw (#90)

Thanks again to @amolenaar, @danyeaw, @dependabot, @dependabot[bot], @sourcery-ai, @sourcery-ai[bot] and Sourcery AI! 🎉