[1/2] Power connect/disconnect notification support

part 1/2: frameworks/base PowerUI and Settings
http://review.cyanogenmod.org/#/c/35241/

part 2/2: packages/apps/Settings Sound settings
http://review.cyanogenmod.org/#/c/35242/

patchset 3:
    shrink a couple of long lines
    remove power_notifications_use_default option (folded into ringtone option)
    load default settings in global instead of system

patchset 5:
    support vibrate toggle
    ignore first power state change (on boot) if it's a DISCONNECT

patchset 6:
    fix ignore first power state change

patchset 7:
    change vibrate to default to off
    simplify first power state change ignore logic

Change-Id: I36a6b9f924d2cd52191a8e83a744745b37c5b068