Implement sharpen

bug:7279964
bug:7247494
bug:7234321

- add a sharpen filter
- add infrastructure to use RenderScript
- some refactoring (add an ImageSlave class)
- add new zoom UI

Change-Id: Id94dc94d32866c7107b6818adf4db35d0c6c0b01
diff --git a/res/layout/filtershow_activity.xml b/res/layout/filtershow_activity.xml
index 0dead60..1449f16 100644
--- a/res/layout/filtershow_activity.xml
+++ b/res/layout/filtershow_activity.xml
@@ -125,6 +125,12 @@
                 android:layout_height="wrap_content"
                 android:visibility="gone" />
 
+            <com.android.gallery3d.filtershow.imageshow.ImageZoom
+                android:id="@+id/imageZoom"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:visibility="gone" />
+
             <ImageButton
                 android:id="@+id/showOriginalButton"
                 android:layout_width="64dip"