Fixed build with newer versions of the ADT.
Avoid crashing if the ad-hoc packet thread can't be created. (Todo: alternative for eth0?)
Added a singleton class to help with InetAddress mappings. Also, in Sim Mobility mode we use eth0 and wlan0 for the ID. (We may expand this to RoadRunner mode later.)
In SimMobility mode, IDs are now proper "long" variables that mirror their (decimal) IP addresses.