Fix bug, add tests, and cli output

api/allocations.go

@@ -62,6 +62,7 @@ type Allocation struct {
 type AllocationMetric struct {
 	NodesEvaluated     int
 	NodesFiltered      int
+	NodesAvailable     map[string]int
 	ClassFiltered      map[string]int
 	ConstraintFiltered map[string]int
 	NodesExhausted     int