[TIMOB-8836] BlackBerry: Implement UI.Tab elements needed for KitchenSink

A tab instance for a TabGroup<http://docs.appcelerator.com/titanium/2.0/#%21/api/Titanium.UI.TabGroup>. A TabGroup tab instance. Each tab includes a button and one or more windows, which holds the "contents" of the tab. Users can select a tab by clicking on the tab button. In iOS, this actually is more of a combination of UITabBarItem and UINavigationController meant to go into a tab group. Android does not have a navigationController concept, so it depends on what Blackberry provides. https://developer.apple.com/library/ios/#documentation/UIKit/Reference/UITabBarItem_Class/Reference/Reference.html#//apple_ref/doc/c_ref/UITabBarItem<https://developer.apple.com/library/ios/#documentation/UIKit/Reference/UITabBarItem_Class/Reference/Reference.html%23//apple_ref/doc/c_ref/UITabBarItem> https://developer.apple.com/library/ios/#documentation/UIKit/Reference/UINavigationController_Class/Reference/Reference.html#//apple_ref/doc/c_ref/UINavigationController<https://developer.apple.com/library/ios/#documentation/UIKit/Reference/UINavigationController_Class/Reference/Reference.html%23//apple_ref/doc/c_ref/UINavigationController>