Compares two "files" entries to find deleted files/folders.
public JInstaller->findDeletedFiles ($old_files, $new_files)
|$old_files||array||An array of objects that are the old files|
|$new_files||array||An array of objects that are the new files|
array An array with the delete files and folders in findDeletedFiles[files] and findDeletedFiles[folders] resepctively