WallpaperCropper: German translation

PS1: German translation, copy strings.xml from AOSP
PS2: add a space to lockscreen_image_reset

Change-Id: I3314aa3105297abb37cda9224f11e6d37891d2aa
Signed-off-by: Matthias Freund <matthias88freund@gmail.com>
Merge "WallpaperCropper: German translation" into kitkat