Ability to "check-in" episodes

Let users to "check-in" episodes when they are watching right now.

Check in info will be synced with Trakt.
While an episode is "check in", users cannot mark any other media as check-in.
A permanent info view will be shown in the app while the episode is watching.
The check-in will end automatically and mark the episode as "watched". An info alert will shown.

javikr / sofatime