Settings: create cm string for wallpapers

Change-Id: I21af266bb0aeff7598082d998b2c2e8d6bbbe187
Merge remote-tracking branch 'upstream/cm-11.0' into cm-11.0
[WIP] SlimPIE (2/2)

Change-Id: I10e026e76748b1e273d38a983ea873a7076b124d