give index when card select

[shenghou]

i think we should add index when the card been selected, so you can order by what you select ;

``
var index = 0;
Descriptor.prototype.$$link = function $$link (scope, elem, attrs, nullController, transclude) {
scope.clickCard = function(card){
index +=1;
scope.clickMedia(card);
card.card.index = index ;
};
......
};