Restructured the 'freeze' property a bit. We now have

Restructured the 'freeze' property a bit.  We now have
  /sim/freeze/master      (implimented)
  /sim/freeze/fuel        (implimented)
  /sim/freeze/position    (not implimented)
  /sim/freeze/time-of-day (not implimented)

/sim/freeze/master is bound to the 'p' key via keyboard.xml, however,
/sim/freeze/fuel is not bound to anything at the moment so you must
change it via the external property interface, or specify an initial
value on the command line.