Added private constructor to utility class

src/main/java/de/cebitec/common/sequencetools/intervals/cache/IntervalCaches.java

@@ -28,6 +28,9 @@ import java.util.List;
  */
 public class IntervalCaches {
 
+    private IntervalCaches() {
+    }
+
     /**
      * Only For debugging and testing purposes.
      */