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/alert_tests.cpp

@@ -2,14 +2,18 @@
 // Unit tests for alert system
 //
 
-#include <boost/foreach.hpp>
-#include <boost/test/unit_test.hpp>
-#include <fstream>
-
 #include "alert.h"
+#include "data/alertTests.raw.h"
+
 #include "serialize.h"
 #include "util.h"
-#include "data/alertTests.raw.h"
+#include "version.h"
+
+#include <fstream>
+
+#include <boost/filesystem/operations.hpp>
+#include <boost/foreach.hpp>
+#include <boost/test/unit_test.hpp>
 
 #if 0
 //