Improve notification shade collapse code.

- Collapse after dismissing the last notification
- Avoid duplicate code paths for collapsing
- Improve variable naming according to AOSP review suggestions

Change-Id: Ic6f26a61f263c5beebbcc9725fe8914d3858576f

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java
	packages/SystemUI/src/com/android/systemui/statusbar/NotificationData.java

Conflicts:
	packages/SystemUI/res/values/ids.xml
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java
	packages/SystemUI/src/com/android/systemui/statusbar/NotificationData.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
	packages/SystemUI/src/com/android/systemui/statusbar/policy/NotificationRowLayout.java
Do not show settings button show quicksettings button instead

Change-Id: I8aa1b6577c6379a8d8d32c6d80a4dfdc7c9efa93

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