Add appropriate animations to ZoomListView and listener to notify any observers when a longClickEvent occured

[SundeepK]

ZoomListView is unfinished and needs to be competed. Some things that need to be done is adding animations, fixing issues with on click events while the listview is zoomed and add a Listener to allow observers to be notified when the listview is Zoomed.

[SundeepK]

This functionality is implemented, however, there are some slight issues with listview items not re-sizing correctly when going back to their original state. This is probably because of the scale animation that is performed when an item gains focus via a longClick, so need to look into it.