Merge pull request #839 from liuchuangww/develop

Fix tag module
Refactored category management
Refactor media management
Added block body display mode support
Merge pull request #840 from linzongshu/develop

Refactored category management
Added block body display mode support
Fix for system module upgrader
Text correction
Refactored custom form page
Refactored statistics page and some APIs
Refactored topic management
Merge pull request #843 from linzongshu/develop

Refactored custom form page
Refactor article lists management
Fix item link
Tag list update
Tag list update
Merge pull request #845 from sexnothing/develop

Tag list update
Refactored user privacy setting
Merge branch 'develop' of https://github.com/pi-engine/pi into develop
Refactored draft edit page