Merge of Aniqua's code with minor modifications into main shout repo. Some of the functions added to meascli.py and measiface.py are duplicating some functionality that exists in the original code, but in general they extend capabilities to include GPS capture for shuttles. For example, I think _do_meas_power and _do_rssi in meascli.py should be the same function, but they differ in how the measurements are encoded.