Easier testing of Eloquent query SQL

This might be of interest to make for more thorough testing of what SQL eloquent builders generate. Using mockery we can create small mocks that work as gateways to the query grammar and processor classes, which allows us to test the generated SQL and bindings from an eloquent query.

This pull request will fail in Travis as I provided an example which catches a current bug (it passes with the change my other pull request added).