OmniGears: updgrade network traffic meter

*Implements list preferences where applicable to simplify the settings
*Add the ability to track Upstream, Downstream, or both
*Add the option to change the frequency with which it updates

Change-Id: I778d981fb7a57d07127608f99d45936a55ae4898

Conflicts:

	res/values/custom_arrays.xml
	src/org/omnirom/omnigears/interfacesettings/BarsSettings.java