[Feature Request] Watched/Unwatched toggle at season and show level

Hi there, 

 

I'd like to bring to attention a rather useful feature in the Plex/Web client that appears to be missing from PHT... The watched/unwatched toggle at season and show level...

 

In the Plex/Web client, this appears in the menu options bar on the left as either a round dot with a tick cutout or dash cutout depending on whether everything at that level is watched or unwatched...

 

I believe this would be great in the PHT client also, as it moves some of the simple database management to a more front end client... I find whenever I want to re-watch a show, I need to mark it as unwatched in Plex/Web beforehand...

early 2021 clean-up: implemented (filter on library level)