Fixed a little bug, now server responds 404 instead 500 when
you try to download an inexistent resource.
Merge pull request #44 from IagoLast/master

Server responds 404 instead 500 when you try to download a nonexistent resource.
Added Mozilla Hacks' article about Shiva
Typos in documentation
Added /about resource
MediaDir objects check existence of paths
PEP8 and some cosmetic changes
Renamed VERSION to __version__
Added contributors list to /about resource
Added subtitle to Clients
Added Shiva4J client
Client authors are now lists
Applying the pokemon pattern
Changed Shiva4J author
Removed unused properties
Better docstrings
Replaced JSONResponse(404) with abort(404)

When a 404 was encountered, the JSONResponse object was trying to be
marshalled. The abort function, on the other hand, raises an Exception,
aborting the execution of the script.
Added converter
Implemented ConverterResource URI.
Convertion docs