timestamp precision added

Added explicitly precision to timestamp, to remove unnecessary precision.

```sql
CREATE TABLE testing_table (
 id serial NOT NULL,
 description character varying(255),
 time_without_precision_tz timestamp(0) without time zone NOT NULL DEFAULT now(),
 time_without_precision timestamp(0) without time zone NOT NULL DEFAULT now(),
 time_with_precision_tz timestamp without time zone NOT NULL DEFAULT now(),
 time_with_precision timestamp without time zone NOT NULL DEFAULT now(),
 CONSTRAINT testing_table_pk PRIMARY KEY (id)
)
```

```sql
INSERT INTO testing_table(description)
    VALUES ('some_description_0');
INSERT INTO testing_table(description)
    VALUES ('some_description_1');
```

```yaml
SELECT * FROM testing_table;
-[ RECORD 1 ]-------------+--------------------------
id                        | 1
description               | some_description_0
time_without_precision_tz | 2014-05-14 17:30:07
time_without_precision    | 2014-05-14 17:30:07
time_with_precision_tz    | 2014-05-14 17:30:07.03091
time_with_precision       | 2014-05-14 17:30:07.03091
-[ RECORD 2 ]-------------+--------------------------
id                        | 2
description               | some_description_1
time_without_precision_tz | 2014-05-14 17:30:07
time_without_precision    | 2014-05-14 17:30:07
time_with_precision_tz    | 2014-05-14 17:30:07.03091
time_with_precision       | 2014-05-14 17:30:07.03091
```