AtteanX::Query::Cache -- A prefetching SPARQL query cacher

This module is intended to be installed on a caching proxy, and given
a SPARQL query, it would analyze the query, find parts it can cache,
prefetch those, and lighten the burden on a remote endpoint.

It can also use Triple Pattern Fragments servers where that makes
sense, but it will mostly allow the remote endpoint to do joins.

The current releases should be considered early alphas, they are not
stable and not complete. They are mostly released to ease
collaboration amongst the authors.
