Drop support for Jelly Bean and KitKat

NDK support for these is already gone

app/src/main/java/com/limelight/ui/StreamView.java

@@ -30,7 +30,6 @@ public class StreamView extends SurfaceView {
         super(context, attrs, defStyleAttr);
     }
 
-    @TargetApi(21)
     public StreamView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
     }