[1/2]Base: Option to hide Adb notification icon

Settings: https://gerrit.omnirom.org/#/c/2933/

Change-Id: I5353b76797ec1e4c53bd6fe014f4ef9b6a7f3936
[1/2] SystemUI: Add time-context headers to the notification header

This commit adds image headers to the notification panel header,
based on the date/time. There are pictures for morning, afternoon
and night, as well as special events like Christmas and new
year's eve.
More will be coming, with eventually a way to use an external
(as in, Internet) provider for those pictures.

Change-Id: Ie3321e9a3e0637d6ba8094dd46aee36c41354713

Conflicts:

	core/java/android/provider/Settings.java