Don't use initial caps in example for exported factory function

Author: Lon Ingram

README.md

@@ -27,9 +27,9 @@ This example (`examples/hello.js`) queries Google for 'webdriver' and returns
 the titles of the results.
 
 ```javascript
-var WebDriver = require('selenium-node-webdriver');
+var webdriver = require('selenium-node-webdriver');
 
-WebDriver().
+webdriver().
     then(function (driver) {
         driver.get('http://www.google.com').
             then(function () {

examples/hello.js

@@ -1,6 +1,6 @@
-var WebDriver = require('selenium-node-webdriver');
+var webdriver = require('selenium-node-webdriver');
 
-WebDriver().
+webdriver().
     then(function (driver) {
         driver.get('http://www.google.com').
             then(function () {