Introduce a (very basic) Wikipedia adaptor

- It loads basic information about films
    - Key/value pairs from Film infoboxes
    - Currently, only title and director
        - Directors don't have top-level identifiers/urls, only names
Merge pull request #405 from atlasapi/mbst-7657-wikipedia

First attempt at Wikipedia FilmExtractor
Merge master into stage

(Brings the wikipedia adaptor commits back in line)