Bugfix: Require OrderedTxItems to provide properly scoped accounting entry list

OrderedTxItems returns a multimap of pointers, but needs a place to store the actual CAccountingEntries it points to.
It had been using a stack item, which was clobbered as soon as it returned, resulting in undefined behaviour.
This fixes at least bug #1768.

src/wallet.h

@@ -146,7 +146,12 @@ public:
 
     typedef std::pair<CWalletTx*, CAccountingEntry*> TxPair;
     typedef std::multimap<int64, TxPair > TxItems;
-    TxItems OrderedTxItems(std::string strAccount = "");
+
+    /** Get the wallet's activity log
+        @return multimap of ordered transactions and accounting entries
+        @warning Returned pointers are *only* valid within the scope of passed acentries
+     */
+    TxItems OrderedTxItems(std::list<CAccountingEntry>& acentries, std::string strAccount = "");
 
     void MarkDirty();
     bool AddToWallet(const CWalletTx& wtxIn);