Adapt navigation bar's long press behaviour for pie controls

This commit brings the navigation bar long press behaviour to
pie controls.

Two things will be considered for long press:
* Long press on HOME will open Google Now.
* Long press on BACK will kill an application if enabled within
  the debug options.

Patch Set #2:
* Jacob's colours

Patch Set #3:
* More blueish colours
* Using a longer time out for long press
  (getLongPressTimeout() * 2)
* Moved killForegroundAppication() around

Patch Set #5:
* Shortened long press time out a bit
* Adjust time for info shade dynamically

Change-Id: I8cfa87a5be0678f0452011d85d427439d7cf31e9

Conflicts:

	packages/SystemUI/src/com/android/systemui/statusbar/pie/PieItem.java