add editorconfig file

.editorconfig

@@ -0,0 +1,20 @@
+; EditorConfig is awesome: http://EditorConfig.org
+
+; top-most EditorConfig file
+root = true
+
+; base rules
+[*]
+end_of_line = lf
+insert_final_newline = false
+indent_style = space
+indent_size = 4
+charset = utf-8
+trim_trailing_whitespace = true
+
+; The default indent on package.json is 2 spaces, better to keep it so we can
+; use `npm install --save` and other features that rewrites the package.json
+; file automatically
+[package.json]
+indent_style = space
+indent_size = 2