Path finding fixes:

Track path finding and order book creation time and latency.
Use a ledger snapshot for path finding.
You can't call getCurrentLedger from an unlocked context.
Pathfinding called from the transaction sign function held the master lock.

src/cpp/ripple/OrderBookDB.h

@@ -1,3 +1,7 @@
+
+#ifndef ORDERBOOK_DB_H
+#define ORDERBOOK_DB_H
+
 #include "Ledger.h"
 #include "OrderBook.h"
 #include <boost/shared_ptr.hpp>
@@ -33,7 +37,7 @@ class OrderBookDB
 
 public:
 	OrderBookDB();
-	void setup(Ledger::pointer ledger);
+	void setup(Ledger::ref ledger);
 
 	// return list of all orderbooks that want XRP
 	std::vector<OrderBook::pointer>& getXRPInBooks(){ return mXRPOrders; }
@@ -56,4 +60,6 @@ public:
 
 };
 
+#endif
+
 // vim:ts=4