Update Readme docs

Adding element rendered the editor; otherwise editor wouldn't render for me.

README.md

@@ -29,7 +29,7 @@ Pure JavaScript method
 
 ```HTML
 <script>
-var simplemde = new SimpleMDE(document.getElementById("MyID"));
+var simplemde = new SimpleMDE( {element: document.getElementById("MyID")} );
 simplemde.render();
 </script>
 ```
@@ -38,7 +38,7 @@ jQuery method
 
 ```HTML
 <script>
-var simplemde = new SimpleMDE($("#MyID")[0]);
+var simplemde = new SimpleMDE( {element: $("#MyID")[0]} );
 simplemde.render();
 </script>
 ```