watched status issued with tv episodes

1. When updating watched status for tv episodes based on air-date the query was incorrect, added quotes to date so it works.

2. When fetching tv episodes' watched status the value returned is always 6, because the query always checks for air-date. Added air-date check when it is provided otherwise only use season and episode.
Merge pull request #17 from the-one-/patch-1

watched status issued with tv episodes