Add a watched button to the continue watching pop up

[jackrvan]

If you watch part of an episode and then exit the episode gets added to the continue watching section on the home page. If you click on it you have 2 options. You can continue watching from where you left off or you can restart the episode. I think it would be nice if we could add another option to mark the episode as watched.

[jackrvan]

I already have a solution to this but note this is my first attempt at contributing to this project and my first attempt at contributing to an open source project in general. I forked the repo and then pushed a branch (add-watched-button-to-continue-watching) that has my change. If I have done something wrong I would very much appreciate if someone could explain what I did wrong and I will be more than happy to fix it.