Created by: AndreaClement
Here we add button to come back from a picture preview and set the stream from the camera for a new photo. This will require to put an imagePreview instead of the SurfaceTexture for the preview since the latter does not handle orientations well. By doing so we'll ease the configuration of the "back" button of the smartphone : we want it to behave the same as button mentioned above. Both these button are active ONLY when the imagePreview is visible.