Implement data provider for TheMovieDB

(copied from https://code.google.com/p/lmf/issues/detail?id=85)
The task is to implement a wrapper around the API of TheMovieDB (http://docs.themoviedb.apiary.io/), similar to the YoutubeProvider, so we can link to movie descriptions in the database. Interesting would also be to get a list of all movie titles available in the database.