Add XO code style to alternatives (#169)

* Update StandardJS link

* Add XO to alternatives

Author: LitoMore

README.md

@@ -274,8 +274,9 @@ For the most part, using ESLint is as simple as tweaking a configuration file in
 
 #### Alternatives
 
-- [Standard](https://github.com/feross/standard)
+- [Standard](https://github.com/standard/standard)
 - [JSHint](http://jshint.com/)
+- [XO](https://github.com/xojs/xo)
 
 ## Linting CSS - stylelint