Emit episodes from trakt.tv

The latest/next watched/collected.
Renamed in trakt_emit

When a custom list is provided, S01E01 will be the default "next
episode" for series never marked seen or collected by the user on
trakt.tv
Class name
Little fixes for empty lists
Names
Merge pull request #218 from tarzasai/trakt_latest

Emit episodes from trakt.tv