- Maintenance: Add .editorconfig (to set project-aware indent in IDEs upon line break)

- npm: Add recommended `package.json` properties, `author`, `contributors`, `engines` (set to minimum for peer dep. Mocha 6), `keywords`, `dependencies`
- npm: Add `lint` script
- npm: Update devDeps.

Author: brettz9

.editorconfig

@@ -0,0 +1,15 @@
+; EditorConfig file: https://EditorConfig.org
+; Install the "EditorConfig" plugin into your editor to use
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true
+
+[*.md]
+indent_size = 4