Android tests

Hopefully this fixes the tests in `BaseballCardDetailsAddCardsTest`. The major change is that I added a call to `Thread.sleep()` to cause a delay after selecting a position from the drop-down spinner. This seems to ensure that the position stored in the database is the correct one. There is most likely a better solution using some kind of thread safety mechanism. However, I am quite unfamiliar with multithread programming, so it will take some more work to figure it out.