Adding request function to exported singleton

#316

lib/axios.js

@@ -78,7 +78,10 @@ Axios.prototype.request = function request(config) {
 
 var defaultInstance = new Axios(defaults);
 var axios = module.exports = bind(Axios.prototype.request, defaultInstance);
-module.exports.Axios = Axios;
+axios.request = bind(Axios.prototype.request, defaultInstance);
+
+// Expose Axios class to allow class inheritance
+axios.Axios = Axios;
 
 // Expose properties from defaultInstance
 axios.defaults = defaultInstance.defaults;