[1/2] SystemUI: Add time-context headers to the notification header with updated images and evening

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.

	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java