- Optimization: Re-rerun image optimization per update

- Linting (ESLint): Adjust per now applied rules
- Testing: Accessibility test API update
- Docs: Clarify need for Node.js/npm being installed
- npm: Update devDeps and core-js-bundle copy; add new axe testing peer dep. axe-core

dist/extensions/ext-imagelib.js

@@ -365,6 +365,7 @@ var svgEditorExtension_imagelib = (function () {
                             return $.process_cancel(message);
 
                           case 39:
+                            // eslint-disable-next-line require-atomic-updates
                             transferStopped = true; // Should a message be sent back to the frame?
 
                             $('#dialog_box').hide();