pg_dump data in BKI format

I'm playing with catalog upgrade via BKI format. I enhanced the pg_dump
of BKI output (not patch ready yet). I'm using it for some test now, but
I think It should be useful for some one other, for example some
application with embedded postgres should use own prepared BKI for
database init (with small enhancement in bootstrap mode) and this option
should help to prepare a BKI script from application template database.

Let me know your meaning about integration this enhancement into the
pg_dump.

Thanks Zdenek