更新xcode8以後、編譯項目出現bug
Cannot create __weak reference in file using manual reference counting
錯誤截圖：
Cannot create __weak reference in file using manual refrence counting Cannot create __weak reference in file using manual reference counting 解決方法：
1、點選工程啟動檔案 - TARGETS -Build Settings 2、在下方搜尋框搜尋 weak 3、在Apple LLVM 8.0 - Language - Objective C選項下邊 4、把Weak Reference in Manual Retain Release選項改成Yes即可。
Cannot create __weak reference in file using manual refrence counting Cannot create __weak reference in file using manual reference counting 
