Settings: add user configurable lockscreen shortcuts (2/2)

Change-Id: I6333792830f7357a9f4fcd5d42c479ec60a71915
Signed-off-by: errantzebra845 <errantzebra845@gmail.com>

Conflicts:
	res/values/slim_strings.xml->candy_strings.xml

 Author:    Lars Greiss <kufikugel@googlemail.com>