[2/2] Forward port power connect/disconnect notification support

Original commit info:

    [2/2] 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/

    Change-Id: I7ddd8a47ae4f9a62c586023d151ac42bbe8424c7

    Power sound notifications: fix ringtone picker title

    Change-Id: Ied0a08ec1607b778324e69a7b40bac056235bebf

    Settings: Rename 'Power sounds' to 'Charging sounds' and add summary

    Change-Id: I1cb872917e2d03f0a1c77c25c27f2a0496f9bc05

Change-Id: Ibde52fcd6fd0fabc9eeefc7e6f5a3971527285d7
Brings performance settings up-to-date with cm-10.2

Includes the following cm-10.2 commits:
http://review.cyanogenmod.org/30667 Performance: BootReceiver: set CPU min/max freqs before CPU governor
http://review.cyanogenmod.org/31886 Adding configurability of frequency cap (min/max) files' path.
http://review.cyanogenmod.org/48007 Cleanup: remove useless checks.
http://review.cyanogenmod.org/51295 Cleanup performance settings strings

Change-Id: If94d02745606e9bdca92a89ea7129a44878226a2
Merge "[2/2] Forward port power connect/disconnect notification support" into kk
Merge "Brings performance settings up-to-date with cm-10.2" into kk