Settings : Port lockscreen shortcut configuration

Port lockscreen configuration from cm-10.2

Lockscreen shortcuts: Fix icon pack usage

Change-Id: I1497cece97f90c76c3930a3a004a2d40416e13ed

Center Lockscreen targets

Change-Id: If99b0b7bf7ac4507076b9806e8208bab77fb71a2

Add icon for Lockscreen targets - by @n3ocort3x