Add support for MenuLayer or SimpleMenuLayer

[lindehoff]

I really like Simply.js, great idea. I would like to be able to get a list of items from an API display the result on the Pebble and then be able to select an item and get the action in Simply.js. To be able to do this I think you have to implement MenuLayer or SimpleMenuLayer.

[Meiguro]

Thank you lindehoff, this would definitely be a great feature! Simply.js is very bare bones at the moment, but I hope to make major improvements some time within the next three months. Hopefully this will be among one of them.