Mobile Network Battery Saver Mode

When idle (screen off) switching to 2G can help extend
battery life as 2G generally uses less power than 3G or LTE.

    + 30 seconds after screen turns off, set network type to 2G
    + If a music player is active (playing), do not set network to 2G
    + When device is unlocked, reset to orignial network type

Settings -> More -> Mobile Networks -> Battery saving mode

Change-Id: Ief8f203f157af3a1484966d43fcc07fd160e4ad7
Telephony: Fix network selection array

CAF added more options to this array but all languages still use the AOSP arrays.
Copy the array to cm_arrays.xml (similar to the way we used for app ops).
Translators will have to copy the original AOSP arrays and add the new items.

Change-Id: If6c22a59cf1021bf997d24855f685e00edf37f03