[SQUASHED] [2/2] Status bar Network traffic (ported from OmniRom)

- This codes are not mine, i just addapt them to crDroid sources, an here i'm giving the proper credits
Commits inside and they authors:
@tectas: https://github.com/omnirom/android_packages_apps_OmniGears/commit/2dc8674ba82e76908c73eecb2bb7ec3a5cb99a8e
@Haus1: https://github.com/omnirom/android_packages_apps_OmniGears/commit/cac09fffd0c83b434c8390e6a3d840c22036d98f
@Haus1: https://github.com/omnirom/android_packages_apps_OmniGears/commit/391eaddbf9b68d4338ea3ff3aed35848a43af71f

Change-Id: Ib3cecfe51512853d5ac986600b1aed4250214ae2