camera: Make the popup menu transparent

 * We should never obscure the preview.

Change-Id: I246f82808f1277f719b9bedafb6d3ace833cc48e

camera: Tweak the popup transparency

 * Currently too hard to read with bright images.

Change-Id: Ica2a77491296637c0b56f886bad704b8b4fcd5c8
Camera2: implement exposure compensation settings in video mode

Change-Id: I83a2675e109dc7924cdd9240b26051ac218f532a
Camera: separate settings for color effects

Store color effect settings for the camera and
video camera in their own separate preferences.

Change-Id: I8faa59b8663154737910b338906d27f9736d5ad9
Camera2: implement volume key zoom in video mode

Change-Id: I140e8cfb3e39700f60e40c35b38e92c83a3c26de