PostgreSQL Auto Increment/DEFAULT values fix

Added right brace to view of default value in Auto Increment columns. Added
option to set `nextval('sequence_name')` as DEFAULT value on column.

Unfortunately, I realized that pattern in second change:
`~^\s+DEFAULT\s+\'nextval\\(\'\'(.*)\'\'\\)\'\s*$~`
should be changed to:
`~^ DEFAULT \'\s*nextval\\(\'\'(.*)\'\'\\)\s*\'$~`
to allow whitespace at start and end.