work towards testing w/ a Postgres test data set

circle.yml

src/metabase/driver/generic_sql/query_processor.clj

src/metabase/driver/h2.clj

src/metabase/driver/postgres.clj

src/metabase/driver/query_processor.clj

test/metabase/driver/query_processor_test.clj

test/metabase/test/data/datasets.clj

test/metabase/test/data/generic_sql.clj

test/metabase/test/data/h2.clj

test/metabase/test/data/postgres.clj