0.5.18: Apple Silicon support, icons, feedback when manipulating frames

Happy new year!

Santa brought me a shiny new M4 mac mini, so 0.5.18 adds native Apple silicon (Mx processor) support and tries to fix the aggressive zooming behavior (work in progress). Additionally, custom icons are now used throughout the UI, the 3D viewers try to provide some written feedback when manipulating frames, and the model-level display toggles are now also in the Display menu, in order to make them harder to overlook (they operate separately from toggling things as hidden/shown). There's also a some nice bugfixes, such as a fix to the annoying muscle plot flickering issue (sorry about that).

Read the CHANGELOG.md file in the repository for a comprehensive overview of what has changed.