- Linting: Lint hidden ncurc.js file

- Docs: Add 6.0.0.md migration file
- Docs: Update Contributing, Testing (renamed to Development), Linting and ReleaseInstructions
- Docs: Info on submodules
- npm: Add scripts for updating submodules
- npm: Add `license-badges`, `build-docs`, and `copy` scripts to `prepublishOnly` script
- npm: Bump to 6.0.0

README.md

@@ -25,7 +25,6 @@ works in any modern browser.
 
 ![screenshot](docs/screenshot.png)
 
-
 ## Help wanted
 
 While we have made some recent releases to SVG-edit for bug fixes,
@@ -148,6 +147,8 @@ incorporating SVGEdit. You will need to have Node.js/npm installed.
 
 ## Recent news
 
+- 2020-02-22 Published 6.0.0 License clarifications/updates, PDF export
+    improvements, clipboard `sessionStorage`, and other changes.
 - 2019-11-16 Published 5.1.0 Misc. fixes and refactoring
 - 2019-05-07 Published 5.0.0 Change from `@babel/polyfill`
 - 2019-04-03 Published 4.3.0 Fix for double click on gradient