Added attached properties for UniformCornerRadius and Style. These properties are inherited and can thus be used to manipulate a Card located inside of another UIElement (eg. the Flipper).

Fallback to default(Style) if the TargetType is not Card.

…d property)

You mentioned on stream that fact that derived types would not work for the CardStyle because of the guard which is completely correct. So I loosened up the requirements by using IsAssignableFrom() instead.

Rename operation did not pick up the string literal in these tests