NetStats: Add net stats to system bar.

PS2:
PS3:
Hide net stats view when notification area is disabled.

Change-Id: Ib35dd46b026dab00abe73966105806c54266e466
Network stats small changes
- change default color;
- show speed in B/s, KB/s and MB/s;
- scale down text size to 9dp;

Change-Id: Ife85c87afba052abe8ae5e60c079680b8046f34e