[pvr] check that the file item has a recording tag before we start
operating on it
[pvr] always update metadata (i.e. play count) for items, not just
the first time an item from that particular folder is encountered
[pvr] hopefully fix the folder watched overlay once and for all. We
now start out by assuming all folders are watched, then as we encounter
unwatched recordings we remember those folders and unmark them at the
end of the method