Explicitly returning a zero byte

src/main/java/com/luminiasoft/bitshares/Memo.java

@@ -20,7 +20,7 @@ public class Memo implements ByteSerializable {
     @Override
     public byte[] toBytes() {
         if ((this.from == null) || (this.to == null) || (this.nonce == null) ||(this.message == null)){
-            return new byte[1];
+            return new byte[] { (byte) 0 };
         } 
         
         byte[] result = new byte[this.from.length+this.to.length+this.nonce.length+this.message.length];