Use wallpaper picker added to WallpaperCropper apk.

The code is still here for easier upstream merges.

Change-Id: I97ec1492e8acf7ff6a5ceef00a68f47e6444bf50
Merge "Use wallpaper picker added to WallpaperCropper apk." into cm-11.0
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_packages_apps_Trebuchet into cd-4.4