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/leveldbwrapper.cpp

@@ -3,15 +3,15 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "leveldbwrapper.h"
+
 #include "util.h"
 
-#include <leveldb/env.h>
+#include <boost/filesystem.hpp>
 #include <leveldb/cache.h>
+#include <leveldb/env.h>
 #include <leveldb/filter_policy.h>
 #include <memenv/memenv.h>
 
-#include <boost/filesystem.hpp>
-
 void HandleError(const leveldb::Status &status) throw(leveldb_error) {
     if (status.ok())
         return;