Add VerifyMessage overload that takes byte[]

- We needed an additional overload method for VerifyMessage that takes byte array as oppose to string.

src/External/NBitcoin/BitcoinPubKeyAddress.cs

@@ -58,6 +58,12 @@ public bool VerifyMessage(string message, string signature)
             return key.Hash == this.Hash;
         }
 
+        public bool VerifyMessage(byte[] message, string signature)
+        {
+            PubKey key = PubKey.RecoverFromMessage(message, signature);
+            return key.Hash == this.Hash;
+        }
+
         private KeyId _KeyId;
         public KeyId Hash
         {