added lua module documentaion
added directive documentaion of 'log_escape'
added lua module version
added docs of variable $conn_requests
added docs of 'server_admin', 'server_tag', 'server_info'
fixed the missing div tag
Update core.html
Update http_log.html
Merge branch 'master' of git://github.com/alibaba/tengine-website into update_0717

Conflicts:
	document/variables.html
	document_cn/variables_cn.html
Merge remote-tracking branch 'yaoweibin/update_0717' into update_0717
Merge pull request #33 from yaoweibin/update_0717

Update 0717