Implement read count for vertices

src/main/java/Vertex.java

@@ -23,6 +23,7 @@ public class Vertex implements Serializable, Comparable<Vertex> {
         this.vertexLabel = vertexLabel;
         this.sequence = sequence;
         this.occupancy = occupancy;
+        this.readCount = 1;
     }
 
     public Vertex(SequenceType type, String sequence, Integer occupancy, Integer vertexLabel, Integer readCount) {