SystemUI: Fix crash during notification/theme change

Fixes crashing that could occur when a notification is created
during a theme change. Entries were attempting to be added
to views which did not have a layout pass yet, causing it to fail.

When a theme change occurs, the fix is to halt the ticker and command queue
until a layout occurs.

BUGDUMP-151925

Change-Id: Ic19d26178df673a1d52981a8617415e6fbcb219d
Disable ticker preference [1/2]

Ticker can be annoying when you're getting spammed by an angry girlfriend
and various other girls at the same time.  Lets disable it until the problem
just goes away :D

Change-Id: If886d92b1c54776ea66ac0a8865b1cf7a073502f