Support for pg_dump to dump tables in cluster order if a clustered index is defined on the table, a little hacked in with how the data is passed around and how the order is pulled out of the db. The latter is the only semi-problematic part as you might be able to generate (very odd) table column names that would break the regex used there which would cause the sql query to be invalid and therefore not dump data for that table.  But as long as you don't name an clustered column/function something like "foo ) WHERE" or the like should be ok.

    Pulled from REL9_2_4_P and fixed some merge conflicts

    Conflicts:
    	src/bin/pg_dump/pg_dump.c

Conflicts:
	src/bin/pg_dump/pg_dump.c
add option to disable sequence scanning when dumping with cluster-order