Not readable sign for "success" and "error" in windows console

Dear caolan

Using nodeunit in windows works fine. But the sign for "success" and "error" comes as a "?" in the windows console. Would be nice, if you could use a valid sign for each console (or maybe check the environment and puts a different sign).

Thanks a lot,
Joachim

在 Windows 控制台中运行 nodeunit 以重现该问题，并检查输出中的成功和错误指示符。定位负责这些控制台符号的代码，然后验证这两个指示符在 Windows 上都能渲染为可读字符，同时不使现有输出发生回归。

由索引模型根据 Issue 内容生成。