Add SMS Middleware layer.

Add fix so ordered broadcasts are delivered to system
apps first in the event of a tie. This works around
the issue where terrible apps steal SMS notifications
from the broadcast queue to simply prevent notifications
that could otherwise be removed by a toggle.

Change-Id: I30e38c6c27d339d55a8f9a0f4106185356a9b9a0
(cherry picked from commit afa9fa7e340b06eee744ff1ac0f22d4eedef0149)