Add network usage stats to status bar. [1/2]

PS2:
Get the time delta between updates and use that to show
average bytes per second.

Change-Id: Ib06a713e6d93649ae8c8e5be5fd62c4f44a48416

PS3:
Code cleanup, change default text color and size to fit
AOKP and add ability to change text color.

PS4:
Fix up layout for cleaner spacing and add for tablets.

Change-Id: Ie3cdb038fecfe8cbb9b7a670c50dc7ebd22690e1