Add regress target

Runs the regress tests without installing the extension

sql/test_setup.sql

@@ -1,8 +1,14 @@
+\set ECHO none
+\set QUIET on
 SET client_min_messages TO error;
-CREATE EXTENSION cartodb CASCADE;
+CREATE EXTENSION postgis;
+CREATE EXTENSION plpythonu;
+CREATE SCHEMA cartodb;
+\i 'cartodb--unpackaged--@@VERSION@@.sql'
 CREATE FUNCTION public.cdb_invalidate_varnish(table_name text)
 RETURNS void AS $$
 BEGIN
   RAISE NOTICE 'cdb_invalidate_varnish(%) called', table_name;
 END;
 $$ LANGUAGE 'plpgsql';
+\set QUIET off