translate ngx_http_random_index_module.xml
translate ngx_http_charset_module.xml
Update xml/cn/docs/ngx_core_module.xml
Merge pull request #34 from moonbingbing/master

Thank you very much
Merge pull request #35 from cfsego/master

ngx_core_module
Merge branch 'master' of https://github.com/taobao/nginx-docs-cn into mybranch

Conflicts:
	xml/cn/docs/http/ngx_http_charset_module.xml
three files
Merge branch 'master' of https://github.com/taobao/nginx-docs-cn into mybranch