dequeue_movie plugin

Adds the ability to remove movies from the movie_queue based on the output of a task. The idea behind this plugin is to allow a user to easily sync a remote list, such as a trackt.tv watchlist, with the movie_queue. This is a copy/rework of queue_movie.

Example:
```yaml
  #remove movies from the movie queue if they were marked as watched in trakt.tv
  Movies-Watchlist-Delete:
    disable_plugin: [seen, deluge, seen_movies, exists_movies, email, reject_failed]

    interval: 1 hours
    seen_movies: strict
    seen: local

    trakt_list: 
      username: xxxxx
      password: xxxxx
      api_key: xxxxx
      movies: watched

    crossmatch:
      from:
        - emit_movie_queue: yes
      fields:
        - imdb_id
      action: accept

    dequeue_movies: yes
```