Reduce padding in often-used structs

Reduce the padding in some often-used structs for 64bit machines.
32bit machines should also profit from most changes, but to a
lesser degree.

Change-Id: Ic4c67b94e962731de4f31164c52a372d78944ccc
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>

src/plugins/coreplugin/dialogs/settingsdialog.cpp

@@ -73,11 +73,11 @@ class Category
 {
 public:
     Id id;
+    int index;
     QString displayName;
     QIcon icon;
     QList<IOptionsPage *> pages;
     QList<IOptionsPageProvider *> providers;
-    int index;
     QTabWidget *tabWidget;
 };