Docs: add English language support (#170)

* feat: support lang entry build

* feat: vant support lang switch

* move lang iframe-router to utils & fix router link bug

* add en-US config && add some translation

* chang async. to async_ (support superman cdn)

* add layout translation

* change nav style

* upgrade zan-doc

* fix: doc config

* upgrade zan-doc && remove useless code

* fix changelog generate path

docs/examples-docs/en-US/changelog.md

@@ -0,0 +1,28 @@
+## Changelog
+
+### [0.9.9](https://github.com/youzan/vant/tree/v0.9.9)
+`2017-09-26`
+
+**Improvements**
+- Sku：support Stepper [\#146](https://github.com/youzan/vant/pull/146) [@w91](https://github.com/w91)
+
+**Bug Fixes**
+- fix license error in packages.json [\#144](https://github.com/youzan/vant/pull/144) [@airyland](https://github.com/airyland)
+- fix Waterfall scroll bug [\#145](https://github.com/youzan/vant/pull/145) [@pangxie1991](https://github.com/pangxie1991)
+
+
+### [0.9.8](https://github.com/youzan/vant/tree/v0.9.8)
+`2017-09-24`
+
+**Improvements**
+- add AddressList component [\#138](https://github.com/youzan/vant/pull/138) [@chenjiahan](https://github.com/chenjiahan)
+- modify changelog [\#140](https://github.com/youzan/vant/pull/140) [@chenjiahan](https://github.com/chenjiahan)
+
+**Bug Fixes**
+- fix Sku message render bug [\#142](https://github.com/youzan/vant/pull/142) [@w91](https://github.com/w91)
+
+### [0.9.7](https://github.com/youzan/vant/tree/v0.9.7)
+`2017-09-21`
+
+**Improvements**
+- Checkbox: support shape prop [\#137](https://github.com/youzan/vant/pull/137) [@chenjiahan](https://github.com/chenjiahan)