allow passing uberarchive path to FilamentViewer and expose destroy_viewer

example/android/.gitignore

@@ -6,6 +6,8 @@ gradle-wrapper.jar
 /local.properties
 GeneratedPluginRegistrant.java
 
+.cxx/
+
 # Remember to never publicly share your keystore.
 # See https://flutter.dev/docs/deployment/android#reference-the-keystore-from-the-app
 key.properties