CGUIMediaWindow: add UpdateFilterPath() method extracted from Update()
fix CGUIMediaWindow::OnPrepareFileItems overrides
add IFileItemListModifier interface and CSmartPlaylistFileItemListModifier implementation
add CFileItemListModification to handle all IFileItemListModifier implementations
CGUIMediaWindow: make use of CFileItemListModification
[win32] update VS project files
[osx/ios/atv2] - sync xcode project
Merge pull request #3415 from Montellese/fileitemlistmodifier

Generic CFileItemList modifiers