Nullpointer when setting picture size parameter in Camera1

[jaydeepw]

FATAL EXCEPTION: main
Process: com.google.android.cameraview.demo, PID: 5712
java.lang.NullPointerException
at com.google.android.cameraview.Camera1.adjustCameraParameters(Camera1.java: 320)
at com.google.android.cameraview.Camera1.setAspectRatio(Camera1.java: 164)
at com.google.android.cameraview.CameraView.setAspectRatio(CameraView.java: 332)
at com.google.android.cameraview.demo.MainActivity.onAspectRatioSelected(MainActivity.java: 221)
at com.google.android.cameraview.demo.AspectRatioFragment$1.onClick(AspectRatioFragment.java: 84)
at android.support.v7.app.AlertController$AlertParams$3.onItemClick(AlertController.java: 959)
at android.widget.AdapterView.performItemClick(AdapterView.java: 302)
at android.widget.AbsListView.performItemClick(AbsListView.java: 1196)
at android.widget.AbsListView$PerformClick.run(AbsListView.java: 3054)
at android.widget.AbsListView$3.run(AbsListView.java: 3812)
at android.os.Handler.handleCallback(Handler.java: 733)
at android.os.Handler.dispatchMessage(Handler.java: 95)
at android.os.Looper.loop(Looper.java: 136)
at android.app.ActivityThread.main(ActivityThread.java: 5590)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java: 515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 1280)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 1096)
at dalvik.system.NativeStart.main(Native Method)

[jamesbluecrow]

Some of our users have been experiencing this when opening the camera in a device Galaxy J3(2016 running Android 5.1.

The reason is that we try to access the last PictureSizes item for an AspectRatio and there is no such size for that aspect ratio.

In those case we should be defaulting to the PreviewSizes.

This PR adds that functionality: #207