Added missing parenthesis in StoreList sanity check QUnit test module that prevented code from working. See added parenthesis on last this.last.add line.

Parenthesis is missing in last list.add of new Store and code does not work. Added missing Parenthesis.

// Define a group for our tests
module( 'StoreList sanity check', {
    setup: function() {
        this.list = new StoreList;
        this.list.add(new Store({ name: 'Costcutter' }));
        this.list.add(new Store({ name: 'Target' }));
        this.list.add(new Store({ name: 'Walmart' }));
        this.list.add(new Store({ name: 'Barnes & Noble' })); // Here
    },
    teardown: function() {
        window.errors = null;
    }
});