Modify newaddress request

Wallet saves to file after creating new address, and new address is
included in lookup

Sources/Stratis.Bitcoin.Features.Wallet/DeStreamWalletManager.cs

@@ -100,9 +100,15 @@ namespace Stratis.Bitcoin.Features.Wallet
         {
             Guard.NotNull(accountReference, nameof(accountReference));
 
-            return this.GetWalletByName(accountReference.WalletName)
-                .GetAccountByCoinType(accountReference.AccountName, this.coinType).CreateAddresses(this.network, 1)
-                .Single();
+            var wallet = this.GetWalletByName(accountReference.WalletName);
+
+            var newAddress = wallet.GetAccountByCoinType(accountReference.AccountName, this.coinType)
+                .CreateAddresses(this.network, 1).Single();
+            
+            this.UpdateKeysLookupLocked(new [] {newAddress});
+            this.SaveWallet(wallet);
+
+            return newAddress;
         }
     }
 }
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