HeadsUp: basic Headsup implementation (1/2)

  -enables the HeadsUp notification feature
  -add a HeadsUp qs tile, tile long press will open the do not disturb settings
Ethernet: observe the ethernet on/off state (1/2)

  observe when the qs tile turns ethernet on or off, write it to a Settings.System setting
  allows Settings switch to stay in sync with the tile
  also adding the getBoolean(cr, string, boolean) and putBoolean(cr, string, boolean) methods to Settings.System