Add Chinese website translation.

[JohnGuan]

1. Add zh to lang_list.html .
2. Add nav_zh.html .
3. Add zh layout/theme to display Chinese CC licence.
4. Add zh\about.html translation.
5. Add zh\develops.html translation.
6. Add zh\discuss.html translation.
7. Add zh\download.md translation.
8. Remove old zh\help\1.0.html file
9. Add zh\help\1.0.md translation.
10. Add zh\howto\index.html translation.
11. Add zh\index.html translation.
12. Add zh\thanks.html translation.
13. Add zh\tutorials\index.html translation.
14. Add zh\tutorials\1.0\index.html translation.
15. Add zh\tutorials\1.0\start.md translation.

[JohnGuan]

Hi @ntoll @carlosperate !
Is this request can be merged?