SQL Adapter tests

Hey,

I like the look of the SQL Adapter and in order to get my head around how complete/incomplete it is, I took the time to write some tests.

Ive mostly just copied over the ones that were written for the Array Adapter and tweaked them to get them running for the SQL Adapter. I haven't got as far as putting them all in, but it's a start.

There are currently 5 failing tests. 4 are related to Transactions and one is to do with dates that cropped up in the formotion spec.

Do you know what the plan is for this adapter? Is the plan to get it merged into Master? Is anyone using it? Also there are references to FMDB but I can't see that it is used?

I did consider changing the tests to share them between adapters. But there are some discrepancies in the implementation. Plus I figured a starting point of at least some tests (even if there is duplication) would make a better starting point and make a refactoring easier at a later stage.