Added TMDbAPI class with getMovieDetails method

The constructor for TMDbAPI class takes one String argument which is
used as the API key given by TMDb.
The 'getMovieDetails' method returns a TMDbMovieDetails object with all
the available information about it on TMDb. It's only argument is the
movie ID which can be retrieved by the 'searchMovie' method.
Updated 'TMDbMovie' with constructor and getters
Added 'searchMovie' API method

'searchMovie' method returns a list of 'TMDbMovie' objects containing
basic information for a single movie. The ID attribute from a specific
movie can then be used in the 'getMovieDetails' method for getting
further information.