Add verbose boolean to getrawmempool

Also changes mempool to store CTxMemPoolEntries
to keep track of when they enter/exit the pool.

src/coins.h

@@ -346,6 +346,9 @@ public:
     // Check whether all prevouts of the transaction are present in the UTXO set represented by this view
     bool HaveInputs(const CTransaction& tx);
 
+    // Return priority of tx at height nHeight
+    double GetPriority(const CTransaction &tx, int nHeight);
+
     const CTxOut &GetOutputFor(const CTxIn& input);
 
 private: