Add explicit implementation of Cloneable

ompi/mpi/java/java/Comm.java

@@ -65,7 +65,7 @@
 /**
  * The {@code Comm} class represents communicators.
  */
-public class Comm implements Freeable
+public class Comm implements Freeable, Cloneable
 {
 	public final static int TYPE_SHARED = 0;
 	protected final static int SELF  = 1;

ompi/mpi/java/java/Datatype.java

@@ -52,7 +52,7 @@
 /**
  * The {@code Datatype} class represents {@code MPI_Datatype} handles.
  */
-public final class Datatype implements Freeable
+public final class Datatype implements Freeable, Cloneable
 {
 	protected long handle;
 	protected int baseType;

ompi/mpi/java/java/Info.java

@@ -23,7 +23,7 @@
 /**
  * This class represents {@code MPI_Info}.
  */
-public final class Info implements Freeable
+public final class Info implements Freeable, Cloneable
 {
 	protected long handle;
 	protected static final long NULL = getNull();