docs(README): link to webpack 2 docs (#44)

Author: simon04

README.md

@@ -20,7 +20,7 @@ globals.<p>
 npm i expose-loader --save
 ```
 
-<h2 align="center">Usage</h2>
+<h2 align="center"><a href="https://webpack.js.org/concepts/loaders">Usage</a></h2>
 
 **Note**: Modules must be `require()`'d within in your bundle, or they will not
 be exposed.
@@ -96,8 +96,6 @@ expose only applies to the react module. And it's only exposed when used in the
 bundle.
 
 
-[Documentation: Using loaders](http://webpack.github.io/docs/using-loaders.html)
-
 <h2 align="center">Maintainers</h2>
 
 <table>