Add SMPP 5.0 message_state values

Author: pmoerenhout

jsmpp/src/main/java/org/jsmpp/bean/OptionalParameter.java

@@ -1911,14 +1911,16 @@ public static class Message_state extends OptionalParameter.Byte {
 		 *
 		 */
 		public enum Message_state_enum {
+			SCHEDULED(0),
 			ENROUTE(1),
 			DELIVERED(2),
 			EXPIRED(3),
 			DELETED(4),
 			UNDELIVERABLE(5),
 			ACCEPTED(6),
 			UNKNOWN(7),
-			REJECTED(8);
+			REJECTED(8),
+			SKIPPED(9);
 
 			private byte value;
 
@@ -1997,7 +1999,6 @@ public static class Billing_identification extends OptionalParameter.OctetString
 		public Billing_identification(byte[] value) {
 			super(Tag.BILLING_IDENTIFICATION.code, value);
 		}
-
 	}