Move `COIN` and `CENT` to core.h

Eventually these should end up in `money.h` after monetary
amounts are typedef'ed, but at least they don't belong in `util.h`.

src/core.h

@@ -14,6 +14,9 @@
 
 class CTransaction;
 
+static const int64_t COIN = 100000000;
+static const int64_t CENT = 1000000;
+
 /** 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); }

src/util.h

@@ -34,9 +34,6 @@
 
 class uint256;
 
-static const int64_t COIN = 100000000;
-static const int64_t CENT = 1000000;
-
 #define BEGIN(a)            ((char*)&(a))
 #define END(a)              ((char*)&((&(a))[1]))
 #define UBEGIN(a)           ((unsigned char*)&(a))