Added serialize method for transaction

Author: rg911

src/model/transaction/Transaction.ts

@@ -26,7 +26,6 @@ import { InnerTransaction } from './InnerTransaction';
 import { SignedTransaction } from './SignedTransaction';
 import { TransactionInfo } from './TransactionInfo';
 import { TransactionType } from './TransactionType';
-import { SerializeTransactionToJSON } from '../../infrastructure/transaction/SerializeTransactionToJSON';
 
 /**
  * An abstract transaction class that serves as the base class of all NEM transactions.

src/utility/TransactionMapping.ts

@@ -37,20 +37,4 @@ export class TransactionMapping {
     public static createFromPayload(dataBytes: string): Transaction {
         return CreateTransactionFromPayload(dataBytes);
     }
-
-    /**
-     * Serialize a transaction.
-     * @returns {string} Serialized transaction in binary.
-     */
-    public static serialize(): string {
-        throw new Error();
-    }
-
-    /**
-     * Create transaction class from Json.
-     * @returns {object} Serialized transaction in json object.
-     */
-    public static serializeJson(): object {
-        throw new Error();
-    }
 }