Added more webdriver tests testing against a real browser.

src/components/Button.jsx

@@ -4,6 +4,7 @@ import classnames from 'classnames'
 
 class Button extends React.Component {
   static propTypes = {
+    "data-wd-key": PropTypes.string,
     onClick: PropTypes.func,
     style: PropTypes.object,
     className: PropTypes.string,
@@ -14,6 +15,7 @@ class Button extends React.Component {
     return <a
       onClick={this.props.onClick}
       className={classnames("maputnik-button", this.props.className)}
+      data-wd-key={this.props["data-wd-key"]}
       style={this.props.style}>
       {this.props.children}
     </a>