Change endpoint URLs (close #154)

- styles at /style/{id}/style.json
- rendered tiles at /style/{id}/{z}/{x}/{y}.{format}
- TileJSONs at /style/{id}.json

test/metadata.js

@@ -71,6 +71,6 @@ describe('Metadata', function() {
     });
   });
 
-  testTileJSON('/styles/test-style/rendered.json');
+  testTileJSON('/styles/test-style.json');
   testTileJSON('/data/openmaptiles.json');
 });