Gumdrop Cases has launched its first Apple accessories, including two cases for the unannounced fourth-generation iPhone. The Gumdrop Skin and Moto Skin are form-fitting cases for the fourth-generation iPhone, offering open access to ports and controls and textured surfaces. Both come in a variety of colors and sell for $30. The AirShell is a snap-on polycarbonate hard shell case offering open access to all ports, controls, and the camera, and either…