Added CachedSimpleResource, a resource task that transparently uses the local filesystem to speed up access to remote URIs

The split nature of vfs_read (urllib vs requests) has been removed, because requests is not present by default on most systems and urllib/urllib2 will handle all URI reads
[tmdb] Completed themoviedb.py scraper module

* Emit dc.date and dc.type (genre)
* Fix configuration api url
* Replace title derived from filename (only emit tmdb title)
* Fixed poster being used as fanart instead of backdrop
* Cosmetic: use of both "http://themoviedb.org" and tmdb_base variable has been made consistent (only url now)
* Use CachedSimpleResource for configuration api call