QueryBuilder fixe and feature

I fixed a bug in the each() method on the ObjectStore where only the first item can be accessed using the cursor approach. When using a cursor, the onsuccess function is called multiple times and cursor.continue() re-calls the method with the next value. Using $q.promise, the listener can only be called once with the first item. To continue to allow the caller to select with items to be added to the list, I added a $filter option when creating a QueryBuilder. This option allows the selection of a function to be called for each item in the cursor. It is called with one argument being the value (cursor.value), and if it returns truthy, the item is added to the result set which is eventually returns in the promise resolution. I don't know of another way to allow independent selection of values when using a promise and resolution.