[1/2] Base: add more Power Menu actions

Make the power menu customizable from Menus settings in OmniGears.

added checkboxes for: airplane mode, sound toggles, and a new button for
mobile data toggle.

screenshots: http://goo.gl/ljQ0WA or http://imgur.com/a/THfuZ

part 2: https://gerrit.omnirom.org/#/c/3654/

Change-Id: Ie7d417c898ceeba47eb0c13f6dee934b025beee0