Casper.userAgent() does not require the instance to be started anymore

@@ -5,6 +5,7 @@ XXXX-XX-XX, v1.0.0
 ------------------
 
 - merged PR [#319](https://github.com/n1k0/casperjs/pull/319), fixed [#209](https://github.com/n1k0/casperjs/issues/209) - test duration has been added to XUnit XML result file.
+- `Casper.userAgent()` does not require the instance to be started anymore
 
 2012-12-14, v1.0.0-RC6
 ----------------------

@@ -1586,7 +1586,6 @@ Casper.prototype.toString = function toString() {
  */
 Casper.prototype.userAgent = function userAgent(agent) {
     "use strict";
-    this.checkStarted();
     this.options.pageSettings.userAgent = this.page.settings.userAgent = agent;
     return this;
 };