Bug 1049198: reduce layers in camera viewfinder

scale viewfinder to fit device pixels, not css pixels

do not overflow the hud
Can you also apply these changes to the 'fit' function beneath it? The app is configurable for vendors to either fill or fit the viewfinder to the screen. Although, I'm not sure if this would help in the case of 'fit' depending on the aspect ratio. But, I'd like to see both functions at least act somewhat consistently.