Merge pull request #4 from UweTrottmann/release-2

Version 2 using retrofit.
Fix README: use trakt instead of getManager()
Merge branch 'release-2.0.1'
Start next dev cycle.
Add default state for ExtendedParam, name it just Extended.
Make Extended enums uppercase.
Add user/library/movies endpoints.
Unify user/library/shows endpoints with movie variants.

- Use Extended enum on user/library/shows endpoints again as well.
Added related to MovieService

Added method related to MovieService to get the top 10 related movies to
the one given. Added test case for this method too.
Use enum path param similiar to library endpoints for related movies.
Add basic contributing file.
Fix wording.
Merge branch 'add-contributing'
Merge branch 'add-contributing' into dev
Add deps formatted for maven, update retrofit version.
make TvShowEpisode implements TraktEntity as well
add the last_update field in MediaBase (used in TvShow and Movie) which is usefull in case of sync
add /show/summaries and the extended version
add /movie/summaries and the extended version
fix typo