Merge http://github.com/pi-engine/pi into user
Merge remote-tracking branch 'upstream/user' into user
Achieved image upload
Merge pull request #231 from linzongshu/user

Achieved image upload
Refactoring message module
Refactoring message module
Code cleaning up
Added placeholder for QQ avatar
Typo fix
Merge pull request #232 from sexnothing/user

User module in process
Added source hash for upload avatar
User module in process
Merge pull request #233 from liuchuangww/user

User module in process
User module in process
Merge pull request #234 from liuchuangww/user

User module in process
User module front-end in process