fixed Tester.renderFailureDetails() error details printing

@@ -4,6 +4,7 @@ CasperJS Changelog
 XXXX-XX-XX, v1.0.0
 ------------------
 
+- fixed `Tester.renderFailureDetails()` which couldn't print failure details correctly in certain circumstances
 - fixed `Casper.getHTML()` wasn't retrieving active frame contents when using `Casper.withFrame()`
 - merged PR [#322](https://github.com/n1k0/casperjs/pull/322) - Support number in `Casper.withFrame()`
 - fixed [#323](https://github.com/n1k0/casperjs/issues/323) - `thenEvaluate()` should be updated to take the same parameters as `evaluate()`, while maintaining backwards compatibility.

@@ -983,7 +983,7 @@ Tester.prototype.renderFailureDetails = function renderFailureDetails(failures)
         message = failure.message;
         this.casper.echo(f('In %s:%s', failure.file, line));
         this.casper.echo(f('   %s: %s', type, message || failure.standard || "(no message was entered)"), "COMMENT");
-    });
+    }.bind(this));
 };
 
 /**