Update episodeWatched.js

Fix for the following scenario:
If a user marks an episode as watched, then later marks it as not-watched, then after a restore on a fresh database, the episodes are set incorrectly to watched.
Update SerieCtrl.js

Consistently set episodes vars "watched" and "watchedAt" in the same way that directive episodeWatched.js does.
Merge pull request #117 from garfield69/angular

Consistently save episode vars "watched" and "watchedAt" in the database as the correct value type.