Cleanup code using forward declarations.

Use misc methods of avoiding unnecesary header includes.
Replace int typedefs with int##_t from stdint.h.
Replace PRI64[xdu] with PRI[xdu]64 from inttypes.h.
Normalize QT_VERSION ifs where possible.
Resolve some indirect dependencies as direct ones.
Remove extern declarations from .cpp files.

src/test/transaction_tests.cpp

@@ -1,13 +1,19 @@
-#include <map>
-#include <string>
-#include <boost/test/unit_test.hpp>
-#include "json/json_spirit_writer_template.h"
 
-#include "main.h"
-#include "wallet.h"
+
 #include "data/tx_invalid.json.h"
 #include "data/tx_valid.json.h"
 
+#include "key.h"
+#include "keystore.h"
+#include "main.h"
+#include "script.h"
+
+#include <map>
+#include <string>
+
+#include <boost/test/unit_test.hpp>
+#include "json/json_spirit_writer_template.h"
+
 using namespace std;
 using namespace json_spirit;