Bitcoin-Qt: massive header and cpp cleanup

- try to enforce the same style to all Qt related files
- remove unneeded includes from the files
- add missing Q_OBJECT, QT_BEGIN_NAMESPACE / QT_END_NAMESPACE
- prepares for a pull-req to include Qt5 compatibility

src/qt/macdockiconhandler.h

@@ -3,9 +3,11 @@
 
 #include <QObject>
 
+QT_BEGIN_NAMESPACE
 class QMenu;
 class QIcon;
 class QWidget;
+QT_END_NAMESPACE
 
 #ifdef __OBJC__
 @class DockIconClickEventHandler;
@@ -18,6 +20,7 @@ class DockIconClickEventHandler;
 class MacDockIconHandler : public QObject
 {
     Q_OBJECT
+
 public:
     ~MacDockIconHandler();
 
@@ -31,8 +34,6 @@ public:
 signals:
     void dockIconClicked();
 
-public slots:
-
 private:
     MacDockIconHandler();