Settings: Simplified Chinese Translations

Added and modified strings to reflect recent changes. Partially ported
from CM10.

Patch Set 2: Added Wi-Fi AP priorities and UMS mode translations.

Patch Set 3: Add custom lock screen background and sound-to-vibration
conversion toggle translations.

Patch Set 4: Fix typo.

Patch Set 5: Some adjustments.

Change-Id: I9434458dd29cc272c8c2d0d0c865ec65d24a917f