[cosmetic] use std:: instead of using namespace std in PVRDatabase,
PVRGUIInfo and PVRManager
[cosmetic] use std:: instead of using namespace std in pvr/addons
[cosmetic] use std:: instead of using namespace std in pvr/channels
[cosmetic] use std:: instead of using namespace std in pvr/dialogs
[cosmetic] use std:: instead of using namespace std in pvr/timers
[cosmetic] use std:: instead of using namespace std in pvr/windows