Add pie control optimizations for Phone UI.

This commit brings some pie control tweaks to the Phone UI. These
tweaks make the pie controls react to several conditions that are
are special to the Phone UI. That means that this piece of code
is more deeply embedded within the SystemUI code.

This mostly adds the foloowing behaviour, that is Phone UI
dependent:
* Disable BOTTOM trigger when notification area is expanded
* Disable LEFT and RIGHT trigger when a keyguard is active
* Enable search light feature

Patch Set 3:
* CyanogenMod Code Style.
* setDisabledFlags now belongs to navigation bar callbacks

Patch Set 5:
* Removed duplicated .observe()

Patch Set 10:
* Fixed unintended trigger activation

Patch Set 13:
* Searchlight opens directly on the bottom (on the lock screen)

Patch Set 15:
* Fix conflict/rebase

Change-Id: I551745b69791adca75190c54282be19d85db75a9