Add the query in MySQL exceptions

It's rather annoying to debug invalid queries as it stands - we have to manually turn on `LOG_QUERIES` and watch the console output (which often won't be a viable option in production). I added a "wrapper" around the default connection query, which adds the original query to the exception before being passed to the callback. Makes things much easier!

![](http://puu.sh/cXSQQ/45d987a938.png)