Finalizing the StubCameraControl

Allows us to develop the app without having to interface with a real camera + `gphoto2`.

You can use it by invoking the app with `STUB_CAMERA=true`:

    $ STUB_CAMERA=true coffee app.coffee

Also included some small fs tweaks.

Screenshot of UI as decoupled from camera.
![screen shot 2014-08-18 at 3 08 27 pm](https://cloud.githubusercontent.com/assets/222583/3958894/a0b3ef08-2724-11e4-8e16-81c890d77000.png)