HALO: Option to pause the underlying app (1/2)

- adds an option to pause the active app when using HALO
- this is enabled by default for devices with low memory
- (currently: <640MB RAM available to the kernel)

Conflicts:
	core/java/android/provider/Settings.java
	services/java/com/android/server/am/ActivityStack.java
FW: Statusbar Brightness Slider Correction

Correct the Statusbar brightness slider adjusment option, corrects the issue of the settings not being saved.

Also removed tabs from some code and replaced with plan spaces.

Change-Id: Ic7ae16f449e90b264c0097a0d3b8f351735e4368
[1/2] Add triggers to change profile based on AP

Add data structure mWifiTriggers to store triggers per profile.
Add network change listener to switch to profile

Change-Id: I97e360d7783d3b0e2bbd70fe7a9a866d8c0fa7cd
Reworked transparent layer
When a halo'ed window is opened, the transparent layer will be always visible. It will manage the background dim.
This fixes some apps dimming its sandboxed processes (like chrome).

LayerActivity manages its own lifecycle. When it's focused after paused it finishes itself.

System processes (identified by "android" pkg in SystemUI and system uid in Activity) don't use the layer and still use their own background. This
has been kept this way to not interfere with their activity.
LayerActivity: Corrected lifecycle
Should contemplate the case that the activity gets stopped
Fix little derp causing visual bug

To reproduce, disable halo, and press "clear all notifications" button

Change-Id: Ice7ab62229e27db53ef51fd5df55dbcd0a86358b