Refactor code

Remove forward declarations of Qt types.
Fix header include order.

src/gui/properties/peersadditiondlg.h

@@ -30,11 +30,10 @@
 #define PEERADDITION_H
 
 #include <QDialog>
+#include <QList>
 
 #include "base/bittorrent/peerinfo.h"
 
-template <typename T> class QList;
-
 namespace Ui
 {
     class addPeersDialog;