导出Pinyin基础类，以方便扩展

[lopaz]

No description provided.

[coveralls]

Coverage increased (+1.0e-06%) to 99.949% when pulling 3e211a1 on lopaz:export-Pinyin-class into 320e4a7 on hotoo:master.

[hotoo]

现在有 WebPinyin 和 NodePinyin ，你计划扩展什么？

另外补充下单测。

[hotoo]

3.x 中已经导出了 Pinyin 类。