完成 A Networked Core Data Application
Merge branch 'master' of https://github.com/answer-huang/objcio_cn

# By Di Wu (2) and others
# Via FangYiXiong (1) and YCFlame (1)
* 'master' of https://github.com/answer-huang/objcio_cn:
  recovery
  Update Issue #8 Quadcopter Project.md
  Update Issue #8 Quadcopter Project.md
  add issue 8