add a .editorconfig file, and make a note about it the README

.editorconfig

@@ -0,0 +1,7 @@
+root = true
+[*]
+indent_style = space
+indent_size = 2
+charset = utf-8
+end_of_line = lf
+trim_trailing_whitespace = true

README.md

@@ -72,6 +72,7 @@ Or install it yourself as:
   * [2.7 Global Flags](#27-global-flags)
   * [2.8 Working with Subcommands](#28-working-with-subcommands)
 * [3. Components](#3-components)
+* [4. Contributing](#4-contributing)
 
 ## 1. Overview
 
@@ -777,6 +778,8 @@ You can contribute by posting `feature requests`, evaluating the APIs or simply
 
 This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.
 
+This project uses [EditorConfig](https://editorconfig.org/) to maintain consistent tabbing and file formats. Consider [installing the plugin for your editor](https://editorconfig.org/#download) to help maintain proper code formatting.
+
 ## Copyright
 
 Copyright (c) 2012-2018 Piotr Murach. See LICENSE.txt for further details.