TxQ full queue RPC info (RIPD-1404):

* RPC `ledger` command returns all queue entries in "queue_data"
  when requesting open ledger, and including boolean "queue: true".
  * Includes queue state. e.g.: fee_level, retries, last_result, tx.
  * Respects "expand" and "binary" parameters for the txs.
* Remove some unused code.

src/ripple/rpc/impl/Handler.cpp

@@ -92,7 +92,6 @@ class HandlerTable {
         h.valueMethod_ = &handle<Json::Value, HandlerImpl>;
         h.role_ = HandlerImpl::role();
         h.condition_ = HandlerImpl::condition();
-        h.objectMethod_ = &handle<Json::Object, HandlerImpl>;
 
         table_[HandlerImpl::name()] = h;
     };