Added Guard against +Infinity Objective Values due to Termination

If the search is terminated by a timer thread, it might terminate
between the last call to shouldTerminate() and the evaluate function.
This would cause objective values of positive infinity.
Then, FFA will break with an ArrayIndexOutOfBoundsException.

We now assign positive infinity as fitness to all non-finite objective
values.

src/main/java/aitoa/algorithms/IntFFA.java

@@ -34,10 +34,16 @@ public void initialize() {
   public void assignFitness(
       final FitnessIndividual<? extends Object>[] pop) {
     for (final FitnessIndividual<? extends Object> ind : pop) {
-      ++this.mFrequencies[((int) (ind.quality))];
+      final double d = ind.quality;
+      if (Double.isFinite(d)) {
+        ++this.mFrequencies[((int) (d))];
+      }
     }
     for (final FitnessIndividual<? extends Object> ind : pop) {
-      ind.fitness = this.mFrequencies[((int) (ind.quality))];
+      final double d = ind.quality;
+      ind.fitness =
+          Double.isFinite(d) ? this.mFrequencies[((int) (d))]
+              : Double.POSITIVE_INFINITY;
     }
   }