Custom lockscreen wallpaper [2/2]

Based on commit of ParanoidAndroid on android 4.3

Lockscreen wallpaper: show error if cropping not supported

Custom wallpaper: use PNG

Conflicts:
	res/values/pa_strings.xml
	res/xml/additional_settings.xml
	src/com/android/settings/AOSPAL/AdditionalSettings.java
	src/com/android/settings/SecuritySettings.java