Multiple transactions per account in TxQ (RIPD-1048):

* Tweak account XRP balance and sequence if needed before preclaim.
* Limit total fees in flight to minimum reserve / account balance.
* LastLedgerSequence must be at least 2 more than the current ledger to be queued.
* Limit 10 transactions per account in the queue at a time.
* Limit queuing multiple transactions after transactions that affect authentication.
* Zero base fee transactions are treated as having a fixed fee level of 256000 instead of infinite.
* Full queue: new txn can only kick out a tx if the fee is higher than that account's average fee.
* Queued tx retry limit prevents indefinitely stuck txns.
* Return escalation factors in server_info and _state when escalated.
* Update documentation.
* Update experimental config to only include the % increase.
* Convert TxQ metric magic numbers to experimental config.

src/ripple/core/impl/LoadFeeTrack.cpp

@@ -102,29 +102,6 @@ LoadFeeTrack::scaleFeeLoad (std::uint64_t fee, std::uint64_t baseFee,
     return fee;
 }
 
-Json::Value
-LoadFeeTrack::getJson (std::uint64_t baseFee,
-    std::uint32_t referenceFeeUnits) const
-{
-    Json::Value j (Json::objectValue);
-
-    {
-        ScopedLockType sl (mLock);
-
-        // base_fee = The cost to send a "reference" transaction under
-        // no load, in millionths of a Ripple
-        j[jss::base_fee] = Json::Value::UInt (baseFee);
-
-        // load_fee = The cost to send a "reference" transaction now,
-        // in millionths of a Ripple
-        j[jss::load_fee] = Json::Value::UInt (
-            mulDivThrow(baseFee, std::max(mLocalTxnLoadFee,
-                mRemoteTxnLoadFee), lftNormalFee));
-    }
-
-    return j;
-}
-
 bool
 LoadFeeTrack::raiseLocalFee ()
 {