.gitignore: add Android Studio project files
android: test cleanup

Improve error messages reported by failed async tests (partial change).

Modify BeanUtil to be public & accessible from tests.

Improved BeanUtilTest
 - test Bean object inherits from VirtualObject to test inheritance
 - add test for includeSuperClasses = false
android: fix bug in Model.toMap

Model.toMap must not add properties from all super classes, because
VirtualObject have properties like class/adapter/creationParameters that
are not part of the model.