Added Decision Tree class.
Added no repetition unit test work on decision tree.
Extracted MatchTableModifier class from IslandConflictResolver class. Create edges in decision tree for repeated phrases.
Refactoring: separated the logic from the data structure.
Refactoring: separated out the travel functionality from the unit test.
  Refactoring: Separated variant graph builder utility method out of DecisionTreeCreator class.
Associate a cost with each edge; improved testability.
Made MatchTable class read only. Extracted MatchTableSelection class from MatchTable.
Refactoring: Moved use of Archipelago out of IslandConflictResolver to
MatchTableSelection.
Refactored. Removed all dependencies on Archipelago from the
IslandConflictResolver and MatchTableLinker classes.