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.
No worries. I originally had it that way, but I pulled it out for two reasons:

1. It separates concerns more cleanly. The index doesn't need to know about the DAO and the service layer is able to make some better determinations about which to use and when.
2. It made for cleaner testing. When retrieving `Question` IDs, `QuestionIndex` doesn't need to have the DAO present to find the actual question.

That being said, if it would be better for Mamute's overall style/architecture to have the DAO in `QuestionIndex`, I can certainly move it in.