[2/3] Settings: Battery Saver mode

introduce battery saver mode
this based from what user want or what user do to saving the battery life
this include:
1. Automatically switch mobile network into what user choice and also disable mobile data IF wifi connected to an AP
2. Automatically switch mobile network and disable mobile data IF battery low (battery level can configure)
3. Reduce screen brightness based low battery (this feature will disabled if Auto brightness mode enabled)
4. Not changing network IF on Call or Usb tether enabled or WifiAP enabled
5. Not changing network IF there is Download/upload progress
6. Support For Both GSM and CDMA devices (need someone to test for CDMA devices)
7. every condition has an option :D
8. Restore all network configuration if Smart Radio disabled
9. Add Time Range to start Smart Radio
10. allow device without mobile data support, to using this feature
11. fix inconsistent battery low level
12. rewrite to better performance
13. modified the controller to support battery saver mode
14. add bluetooth, gps, wifi, and mobile data (if support) to be disabled while power saving activated
15. move preference settings into settings => battery settings

Conflicts:
	res/values/custom_strings.xml

Change-Id: I19502c731b74e82a3873f19f51965ee5a88c1f04