refactor app directory structure and add tests

tests/node_modules/nightwatch/lib/api/client-commands/useCss.js

@@ -0,0 +1,27 @@
+var util = require('util');
+var locateStrategy = require('./_locateStrategy.js');
+
+/**
+ * Sets the locate strategy for selectors to `css selector`, therefore every following selector needs to be specified as css.
+ *
+ * ```
+ * this.demoTest = function (browser) {
+ *   browser
+ *     .useCss() // we're back to CSS now
+ *     .setValue('input[type=text]', 'nightwatch');
+ * };
+ * ```
+ *
+ * @method useCss
+ * @param {function} [callback] Optional callback function to be called when the command finishes.
+ * @api commands
+ */
+
+function Command() {
+  this.strategy = 'css selector';
+  locateStrategy.call(this);
+}
+
+util.inherits(Command, locateStrategy);
+
+module.exports = Command;