Clean up LedgerEntrySet and TransactionEngine:

* Reduce public interfaces
* Remove wrapper functions
* Remove freeze timed cutover code
* Return results directly instead of via ref parameters

src/ripple/app/ledger/Ledger.cpp

@@ -261,30 +261,6 @@ Ledger::~Ledger ()
     }
 }
 
-bool Ledger::enforceFreeze () const
-{
-
-    // Temporarily, the freze code can run in either
-    // enforcing mode or non-enforcing mode. In
-    // non-enforcing mode, freeze flags can be
-    // manipulated, but freezing is not actually
-    // enforced. Once freeze enforcing has been
-    // enabled, this function can be removed
-
-    // Let freeze enforcement be tested
-    // If you wish to test non-enforcing mode,
-    // you must remove this line
-    if (getConfig().RUN_STANDALONE)
-        return true;
-
-    // Freeze enforcing date is September 15, 2014
-    static std::uint32_t const enforceDate =
-        iToSeconds (boost::posix_time::ptime (
-            boost::gregorian::date (2014, boost::gregorian::Sep, 15)));
-
-    return mParentCloseTime >= enforceDate;
-}
-
 void Ledger::setImmutable ()
 {
     // Updates the hash and marks the ledger and its maps immutable
@@ -766,7 +742,7 @@ bool Ledger::saveValidatedLedger (bool current)
                     << "Transaction in ledger " << mLedgerSeq
                     << " affects no accounts";
 
-            *db << 
+            *db <<
                (STTx::getMetaSQLInsertReplaceHeader () +
                 vt.second->getTxn ()->getMetaSQL (
                     getLedgerSeq (), vt.second->getEscMeta ()) + ";");
@@ -953,7 +929,7 @@ bool Ledger::getHashesByIndex (
     auto db = getApp().getLedgerDB ().checkoutDb ();
 
     boost::optional <std::string> lhO, phO;
-    
+
     *db << "SELECT LedgerHash,PrevHash FROM Ledgers "
             "INDEXED BY SeqLedger Where LedgerSeq = :ls;",
             soci::into (lhO),
@@ -1024,7 +1000,7 @@ Ledger::pointer Ledger::getLastFullLedger ()
 
         if (!ledger)
             return ledger;
-    
+
         ledger->setClosed ();
 
         if (getApp().getOPs ().haveLedger (ledgerSeq))