Revert "[1/2] Squash Commit: Add time-context headers to the notification header"

This reverts commit fbf7f548cebf65a4e7f80bcdad0ccb6183a2edfa.

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/res/drawable-hdpi/notifhead_afternoon.jpg
	packages/SystemUI/res/drawable-hdpi/notifhead_christmas.jpg
	packages/SystemUI/res/drawable-hdpi/notifhead_morning.jpg
	packages/SystemUI/res/drawable-hdpi/notifhead_newyearseve.jpg
	packages/SystemUI/res/drawable-hdpi/notifhead_night.jpg
	packages/SystemUI/res/drawable-xhdpi/notifhead_afternoon.jpg
	packages/SystemUI/res/drawable-xhdpi/notifhead_christmas.jpg
	packages/SystemUI/res/drawable-xhdpi/notifhead_morning.jpg
	packages/SystemUI/res/drawable-xhdpi/notifhead_newyearseve.jpg
	packages/SystemUI/res/drawable-xhdpi/notifhead_night.jpg
	packages/SystemUI/res/drawable-xxhdpi/notifhead_afternoon.jpg
	packages/SystemUI/res/drawable-xxhdpi/notifhead_christmas.jpg
	packages/SystemUI/res/drawable-xxhdpi/notifhead_morning.jpg
	packages/SystemUI/res/drawable-xxhdpi/notifhead_newyearseve.jpg
	packages/SystemUI/res/drawable-xxhdpi/notifhead_night.jpg
	packages/SystemUI/res/layout/status_bar_expanded_header.xml
	packages/SystemUI/src/com/android/systemui/omni/StatusHeaderMachine.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java