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/mruset_tests.cpp

@@ -1,13 +1,16 @@
-#include <boost/test/unit_test.hpp>
-
-using namespace std;
-
 #include "mruset.h"
+
 #include "util.h"
 
+#include <set>
+
+#include <boost/test/unit_test.hpp>
+
 #define NUM_TESTS 16
 #define MAX_SIZE 100
 
+using namespace std;
+
 class mrutester
 {
 private: