Feature Request: implement resume button

[peledzius]

Sometimes you want to continue watching movie from place where you left off. It's currently not possible with this card, but with Plex API it's possible to resume.

My suggestion: implement Resume button next to Play button. It could look something like this:

If there's nothing to resume(there is no yellow bar in bottom of the poster) - Resume button is hidden or greyed out.

P.S. Thank you for this wonderful card!