[2/2] TrafficMeter: added option for auto-hiding on inactivity

Together with inactivity threshold

Thanks to @C3C0 for the code

Network traffic monitor: add summary to auto hide

also fix disabling autohide options when monitor is disabled

Change-Id: I2e88b946bc6fd2c3e4dbe205e47fbfcd66a68e9f
Merge pull request #18 from LiquidSmooth/kitkat3

[2/2] TrafficMeter: added option for auto-hiding on inactivity