Gallery2: fix for using scaled down image for preview

When using scaled down image for preview, we need to
take previously applied geometry filters into account.
Need to apply geometry filters correctly for smaller sized preview.

Conflicts:
	src/com/android/gallery3d/filtershow/filters/ImageFilterDualCamFusion.java
	src/com/android/gallery3d/filtershow/filters/ImageFilterDualCamSketch.java
	src/com/android/gallery3d/filtershow/filters/ImageFilterDualCamera.java

Change-Id: I4f1e586dde161949626d15185efc993b8b9aae11