Solr search capability

First attempt at issue #9. Adds new indexing capability on create/update/delete, includes embedded Solr and test cases/data. Rebased from master to keep things in sync.
There's a way to avoid that n+1: doing a query searching for all questions in (:ids) and, after that, using session.load to get the questions in the specified order as you're doing (the hibernate would get the questions from the first level cache once you already selected them before). (yeah, its not pretty, but works)