Stop preview after taking picture

 * Workaround bug with pre jb camera libs so that the
   updated camera app in CM11 works properly.
Remove preview workarounds completely

 * Seems to work fine without, and ADC Team did the same.
Fix zooming in preview

Port of:
https://github.com/Dorregaray/camerahal/commit/6ba7ef41c386aa16dbac9aab1922dc3bbbd99eba
Use ION uncached buffers
Fix USB tethering