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/multisig_tests.cpp

@@ -1,18 +1,14 @@
-#include <boost/assert.hpp>
-#include <boost/assign/list_of.hpp>
-#include <boost/assign/list_inserter.hpp>
-#include <boost/assign/std/vector.hpp>
-#include <boost/test/unit_test.hpp>
-#include <boost/foreach.hpp>
-#include <boost/tuple/tuple.hpp>
 
-#include <openssl/ec.h>
-#include <openssl/err.h>
 
+#include "key.h"
 #include "keystore.h"
 #include "main.h"
 #include "script.h"
-#include "wallet.h"
+#include "uint256.h"
+
+#include <boost/assign/std/vector.hpp>
+#include <boost/foreach.hpp>
+#include <boost/test/unit_test.hpp>
 
 using namespace std;
 using namespace boost::assign;