Keeps track of the DOM Elements and other info to monitor changes; ONE (and only one)
Tracker object will exist for each Province with any items to be rendered (SC, units, etc.)
Similar to an OrderResult, but allows the optional specification of:
valid Locations to which a unit may retreat (if any)
the unit that dislodged this unit
the attack and defense strengths
Dependencies for a Convoy order are:
Moves to this space (to determine dislodgement)
Supports to this space (only considered if attacked, to prevent dislodgement)
Dependencies for a Move order:
NOT ADDED:
convoy route, if it is a convoyed move
note that while a move would depend upon a convoy route,
individual convoy orders are not helpful because there may be
multiple paths to a destination.
Dependencies for a Support order:
Moves to this space (for cuts, and dislodgement)
Support to this space (only considered if attacked, to prevent dislodgement)