add IFileItemListModifier interface and CSmartPlaylistFileItemListModifier implementation
add CFileItemListModification to handle all IFileItemListModifier implementations
[win32] update VS project files
CGUIMediaWindow: make use of CFileItemListModification
CGUIViewState: extend AddPlaylistOrder() to handle smartplaylist-specific sorting information
CGUIViewStateVideo: add support for smartplaylist-specific sort information
CGUIViewStateMusic: add support for smartplaylist-specific sort information
CGUIViewState: rename AddPlaylistOrder() to AddAndSetSortMethod()