* Assign commandId to async commands

* CommandListener refactor

Pull listener out of Navigator and implement NativeCommandListener for native commands

* Emit onNavigationEvent when commands complete

* Rename timestamp to completionTime

* Rename NavigationEvent to EventEmitter

* Rename sendOnNavigationButtonPressed to emitOnNavigationButtonPressed

* Emit navigationEvent on bottom tab select

* rebase fix

* Emit commandCompleted event instead of nativeEvent

* fix native ios commands

* wait show and dismiss Overlay