Merge pull request #837 from voltan/develop

Improve update script
Add user custom doc
Update readme-user-custom.md
Refactored author management
Merge pull request #838 from linzongshu/develop

Refactored author management
Fix tag module
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