Add property to limit size or number of items

[Bill Burgess]

I'd love to see the ability to restrict how for the menu comes into view. Primarily to drop the menu down into place, but still be able to see part of the content underneath. Mainly how the Vine app is doing it, but when you have enough items to completely fill the screen.

As an addition, the ability to scroll the list of menu items is an absolute must. I see a pull request for it, so implementing a size limit with a scroll view would be perfect. Thanks!