Fixes popcorn-team/popcorn-app#168

Add a "Get more..." button showing up when there are not enough movie to fill the screen so the user can't scroll down. The button is not showing if there is a scrollbar or if the user did a search.
![screenshot - 200314 - 02 46 18 am](https://f.cloud.github.com/assets/1420974/2469439/5fb43328-affb-11e3-8113-779179fed4df.png)