Summary:
This diff fixes the warnings raised from FlipperKit. Also this diff updates the deployement target of FlipperKit to iOS 10. Even wilde assumes the min deployment OS version to be iOS 10. In layout plugin we use [UIAccessibiltyTraiTabBar](https://developer.apple.com/documentation/uikit/uiaccessibility/uiaccessibilitytraits/1648592-tabbar), which assumes iOS 10 and above.
Partially fixes https://github.com/facebook/flipper/issues/803
Still there are some warnings which are coming from the dependencies outside of Flipper.
Reviewed By: passy
Differential Revision: D19941558
fbshipit-source-id: 31809fedb9aa297bc318b5af72e29e8444f0142f
972277b031