Change Chronus to cLock

Modifying rootbox settings link to Cyanogenmod Lock Clock to reflect naming change.

See:
https://plus.google.com/+CyanogenMod/posts/7Ln7ehDyNDN
https://plus.google.com/+CyanogenMod/posts/UhTtrzAWf1s

FYI, this is my first time working with Android and git. I have tested it on my d2att and the change works as expected, but please make sure that what I have done isn't going to break something.

Thanks for the work you put into this ROM.

Ryan