Build native iOS 8 keyboard extension

I need a native iOS 8 keyboard that supports both landscape and portrait modes. The keyboard should be identical to iOS8's keyboard with the ABC, 123, and special characters. The keyboard should be compatible with the iPad and scalable. My end goal is to create a theme-able keyboard system so the code needs to be clean and structured so that it can easily be updated. The keyboard does not need autocorrect, or any of the actual keys to work as I can add that functionality at a later time. I just need the buttons laid out on the InputView and they should autoresize when the orientation is changed.