Add html file with metadata for testing
Add html file with metadata for testing

* Add test_files directory
* Add turtles.html

Turtles.html contains dublin core, open graph,
twitter, and general metadata.

wikimedia/html-metadata,iSCInc/html-metadata,d00rman/html-metadata,davemorro/html-metadata,wikimedia/html-metadata,iSCInc/html-metadata,martindale/html-metadata,davemorro/html-metadata,d00rman/html-metadata,GEOFBOT/html-metadata,martindale/html-metadata,GEOFBOT/html-metadata