[cordova] Add cordova mobile spec tests
[usecase-webapi] Optimize main.js.

- When back to home page, the selected set can show case list.
- When repeated case in XML file, home page can show correctly.
[cordova] Add cordova mobile spec tests
Merge pull request #8 from JianfengXu/xujf/optimize

[usecase-webapi] Optimize main.js.
[webapi-usecase] Add README for samples
Merge pull request #6 from JianfengXu/xujf/readme

[webapi-usecase] Add README for samples