SystemUI: Avoid "phantom" status bar collapsing

There is one specific case where the status bar may collapse
for no aparent reason: When the last notification is removed.

If Quick Settings panel is showing while such a notification
is removed, the status bar WILL collapse -- and the user may
be left wondering why, because the notification that was just
removed isn't visible in that case.

A way to reproduce this behaviour follows:
  1) Settings -> System -> Quick Settings Panel -> uncheck
     "Auto close panel"
  2) Dismiss all notifications, even the sticky ones.
  3) Open the Quick Settings Panel and tap the apropriate
     tile to light the Torch
  4) Tap the tile again, to extinguish the Torch.

As you can see, the Quick Settings Panel collapses. This
happens because Torch puts up a notification, when lit and
removes it, just after it's turned off.

This will happen to whatever notification that hides itself,
e.g. a GMail notification, which vanishes when you read the
e-mail on another device. This too will trigger this issue.

-----

This patch prevents the bar from collapsing, as consequence
of removing the last notification, when Quick Settings is
showing.

Change-Id: I8c7c015c836810a465268b25b90c9166c4485a9f
PIE: animation revamped (back to the first draft), style changes

Change-Id: I9e521ed4f7be2df629f58d933bad286486ec4a71

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/view/PieMenu.java
Policy: fix keyguard statusbar showing while in ext desktop, fixes it in
apps like currents as well

Change-Id: Id3e4b99d60c33e4050e0e97c365d1ae739f603ec
Low battery warning policy (1/2)
Option to choose how low battery warning will be indicated
- Popup dialog and sound
- Popup dialog only
- Sound only
- Off

Change-Id: I9e4f984f89cab8fab626ea1e8e03d7123a8b3cb5