- 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

.eslintrc.js

@@ -69,7 +69,7 @@ module.exports = {
       }
     },
     {
-      files: '.eslintrc.js',
+      files: ['.eslintrc.js', '.ncurc.js'],
       extends: [
         'plugin:node/recommended-script'
       ],