Reduce Hashing to one call

Author: neutralleiter

core/src/main/java/eu/bittrade/libs/steemj/base/models/SignedTransaction.java

@@ -165,7 +165,7 @@ public void sign(String chainId) throws SteemInvalidTransactionException {
             Sha256Hash messageAsHash;
             while (!isCanonical) {
                 try {
-                    messageAsHash = Sha256Hash.wrap(Sha256Hash.hash(this.toByteArray(chainId)));
+                    messageAsHash = Sha256Hash.of(this.toByteArray(chainId));
                 } catch (SteemInvalidTransactionException e) {
                     throw new SteemInvalidTransactionException(
                             "The required encoding is not supported by your platform.", e);