Option to hide network speed indicator when there is no traffic (1/2)

Change-Id: Id77f746092100dd8dee9c3761f224a8167e56516

Conflicts:

	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/policy/Traffic.java

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/policy/Traffic.java