FwBase: Transparent NavBar

Added a transparent mode to the NavigationBar

Change-Id: Ic72f8ea29c31a087b1a0f4672a57c91b39dfd017
Signed-off-by: STELIX <ssspinni@gmail.com>
Merge commit 'refs/changes/80/580/1' of https://review.carbonrom.org/CarbonDev/android_frameworks_base into kitkat