pgsql: specialized casts for _recreate_copy_table()
pgsql: specialized casts for _recreate_copy_table()

Current PostgreSQL versions wont allow an ALTER COLUMN between varchar
and bytea (blob) without an explicit cast. This pull request adds this
casts for both directions and fixes sequence name detection to
understand newer ::regclass instead of ::text in defaults.

Fixes #207

Signed-off-by: Damien Regad <dregad@mantisbt.org>

Original commits in PR #207 squashed and message reworded.

ipso/ADOdb,ipso/ADOdb