add `onAppear` and `onDisappear` JS callbacks to view API
add `onAppear` and `onDisappear` JS callbacks to view API

TheHolyGrail/Zoot,Electrode-iOS/ELHybridWeb,TheHolyGrail/Zoot,kuruvilla6970/Zoot,kuruvilla6970/Zoot,kuruvilla6970/Zoot,Electrode-iOS/ELHybridWeb