Data-generated widgets fail to recognize passed in IDs

[Josh Williams]

_prepItem generates a domID, even if you pass in an id via the content array

$('#container').ScrollStory({
    content: [{hed:'Headline1', id:'myid1'}, {hed, 'Headline2', id: 'myid2'}]
    itembuild: function(ev, data) {
        data.item.el.html('<h2>'+data.item.domData.hed+'</h2>');
    }
});

_prepItem should probably be something like this:

// use exisiting ID or generate a new one
if ($el.attr('id')) {
    id = $el.attr('id');
} else if (data.id) {
    id = data.id;
    $el.attr('id', id);
} else {
    id = 'scrollStory_story_' + index;
    $el.attr('id', id);
}