add recent apps GB style action to navbar buttons (1/2)

This will add the option to open the Gingerbread style
recent application dialog.
This is the dialog that will show when doing <Alt><Tab> with
a bluetooth keyboard.

Change-Id: Id7894b698c43683467d7e8283b4b2b3dd1946f87
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>
SystemUI: transparency control overhaul

Allow more customization. TransparencyManager's responsibility
is to apply the values it is being fed from Settings.System set by
ROMControl.

Tablets do not use transparency currently, but it shouldn't throw
any errors.

Change-Id: I11c1578938e337285d99e9fa1fbbd537a4ee43ec
Signed-off-by: Roman Birg <romanbirg@gmail.com>

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/NavigationBarView.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBarView.java

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/TransparencyManager.java
	packages/SystemUI/src/com/android/systemui/statusbar/NavigationBarView.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBarView.java