This change adds `Accept-Encoding: gzip` to all outbound requests from the live crawler and feed fetcher, and the corresponding decoding logic for the compressed response data.
The change addresses issue #136, save for making the fetcher's requests conditional.
To avoid hammering the same invalid URLs for up to two months, URLs that fail to fetch correctly are on a dice roll added to a bad URLs table, that prevents further attempts at fetching them.
