settings: add ISettingsHandler
CPlayerCoreFactory: implement ISettingsHandler
CRssManager: implement ISettingsHandler
CUPnPSettings: implement ISettingsHandler
CAdvancedSettings: implement ISettingsHandler
CApplication: implement ISettingsHandler
settings: add ISubSettings
CSettings: now we can savely call Clear() again from the destructor
settings: move skin settings into CSkinSettings
settings: move source settings into CMediaSourceSettings
settings: move view state settings into CViewStateSettings
settings: move watched and video settings into CMediaSettings
[win32] update VS project files