Fixed|OS X: Build error with Qt 4.7

In Qt 4.7, QThreadStorage requires a pointer type.
libappfw|GuiWidget: Manually saving/restoring widget tree state

Sometimes it is beneficial to save/restore state at other times
in addition to widget de/initialization.
Fixed|UI|Client: Update singleplayer session menu when game changes

The currently loaded game is disabled in the menu, so it has to be
enabled when returning to ring zero.
Fixed|UI|Client: Games dialog sort order should match Home Screen order

The Ring Zero game selection menu hangs around in the background,
so its state must be manually saved so the Games dialog uses the
correct state.