写这篇的目的是为了看看xcode8会遇到多少问题，
1、Xcode8:"subsystem: com.apple.UIKit, category: HIDEventFiltered, enable_level: 0" 的警告
subsystem: com.apple.BackBoardServices.fence, category: App,
enable_level: 1, persist_level: 0, default_ttl: 0, info_ttl: 0, debug_ttl: 0,
generate_symptoms: 0, enable_oversize: 0, privacy_setting: 0,
enable_private_data: 0
解决警告方法：