Support for modules which export React elements

This adds support for modules which export React elements:

    export default (
      <div>
        Hello, world!
      </div>
    )

Which is nice as it saves us from boilerplate we don't need.

Hot reloading feature is preserved.

dummy.js

@@ -1,3 +1,17 @@
-var React = require('react')
+var React     = require('react')
 var Component = require('theydoitonpurposelynn')
-React.render(<Component/>, document.querySelector('#app'))
+
+function render(Component) {
+  if (!(Component.type && Component.props)) {
+    Component = <Component />;
+  }
+  React.render(Component, document.querySelector('#app'))
+}
+
+render(Component);
+
+if(module.hot) {
+  module.hot.accept("theydoitonpurposelynn", function() {
+    render(require("theydoitonpurposelynn"));
+  });
+}