Refactor: move GetValueIn(tx) to tx.GetValueIn()

GetValueIn makes more sense as a CTransaction member.

src/core.h

@@ -14,6 +14,10 @@
 
 class CTransaction;
 
+/** No amount larger than this (in satoshi) is valid */
+static const int64_t MAX_MONEY = 21000000 * COIN;
+inline bool MoneyRange(int64_t nValue) { return (nValue >= 0 && nValue <= MAX_MONEY); }
+
 /** An outpoint - a combination of a transaction hash and an index n into its vout */
 class COutPoint
 {
@@ -217,6 +221,11 @@ public:
     uint256 GetHash() const;
     bool IsNewerThan(const CTransaction& old) const;
 
+    // Return sum of txouts.
+    int64_t GetValueOut() const;
+    // GetValueIn() is a method on CCoinsViewCache, because
+    // inputs must be known to compute value in.
+
     bool IsCoinBase() const
     {
         return (vin.size() == 1 && vin[0].prevout.IsNull());