adding api to get trx id from trx

libraries/wallet/include/graphene/wallet/wallet.hpp

@@ -700,6 +700,12 @@ class wallet_api
       }
 
 
+      /**
+       *  This method is used to convert a JSON transaction to its transactin ID.
+       */
+      transaction_id_type get_transaction_id( const signed_transaction& trx )const { return trx.id(); }
+
+
       /** These methods are used for stealth transfers */
       ///@{
       /**
@@ -1483,6 +1489,7 @@ FC_API( graphene::wallet::wallet_api,
         (borrow_asset)
         (transfer)
         (transfer2)
+        (get_transaction_id)
         (create_asset)
         (update_asset)
         (update_bitasset)