Consolidate CTransaction hex encode/decode into core_io.h, core_{read,write}.cpp

src/core_write.cpp

@@ -0,0 +1,15 @@
+
+#include "core_io.h"
+#include "core.h"
+#include "serialize.h"
+#include "util.h"
+
+using namespace std;
+
+string EncodeHexTx(const CTransaction& tx)
+{
+    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
+    ssTx << tx;
+    return HexStr(ssTx.begin(), ssTx.end());
+}
+