Ignoring of duplicate itemID in addTower.
Plurals are hard.
Address missing data, as API can return None.
Pulse time implementation correction

  - It turns out onlineTimestamp isn't really the "tick" time used, it's
    it's stateTimestamp.
  - This is what happens when I finally have access to a real set of API
    keys, fun discoveries happen.
Handle partially initialized fuels.
A demo manager that integrates API with tracker.

  - A simple test bed for accessing the API.
Timestamps are hard apparently.
With the actual data timestamp, life is easier.

  - Since it turns out the stateTimestamp is completely irrelevant to
    the actual fuel levels.  As the tower fuel setting method already
    synchronize with the stateTimestamp, just use currentTime.