Add not-working-yet text box, plus a bit more css

src/molecules/MessageComposer.js

@@ -0,0 +1,16 @@
+var React = require('react');
+
+var MatrixClientPeg = require("../MatrixClientPeg");
+
+module.exports = React.createClass({
+    render: function() {
+        return (
+            <div className="mx_MessageComposer">
+                <form>
+                    <textarea />
+                </form>
+            </div>
+        );
+    },
+});
+