psql tab-complete patch #3

Hi all!

Attached is the third version of my patch that adds/fixes several things
to/in the psql-tabcomplete code.
This diff includes the still missing tab-complete support for TABLESPACE
I already sent earlier.
New in this version of the patch is a small adaption of the tab-complete
code to support the adjusted SAVEPOINT-Syntax commited by Tom, as well
as completion of the only half working (and I think only by accident)
tabcomplete-suppport for "BEGIN [ TRANSACTION | WORK ]".

As I already stated earlier I'm by no means a programmer, and I would
love to get at least some feedback if there is even the slightest
interest in(or since some of the changes may qualify as feature
enhancements, most of this is not 8.0 material).

below is a complete list of the things I have changed with this patch:

*) add tablespace support for CREATE/DROP/ALTER and \db
*) sync the list of possible commands following ALTER with the docs (by
adding
AGGREGATE,CONVERSATION,DOMAIN,FUNCTION,LANGUAGE,OPERATOR,SEQUENCE,TABLESPACE
and TYPE)
*) provide a list of valid users after "OWNER TO"
*) tab-complete support for ALTER (AGGREGATE|CONVERSION|FUNCTION)
*) basic tab-complete support for ALTER DOMAIN
*) provide a list of suitable indexes following ALTER TABLE <sth>
CLUSTER ON(?)
*) add "CLUSTER ON" and "SET" to the ALTER TABLE <sth> - tab-complete
list(fixes incorrect/wrong tab-complete with ALTER TABLE <sth> SET
+<TAB> too)
*) provide a list of possible indexes following ALTER TABLE <sth> CLUSTER ON
*) provide list of possible commands(WITHOUT CLUSTER,WITHOUT OIDS,
TABLESPACE) following ALTER TABLE <sth> SET
*) sync "COMMENT ON" with docs by adding "CAST","CONVERSION","FUNCTION"
*) add ABSOLUT to the list of possible commands after FETCH
*) "END" was missing from the sql-commands overview (though it had
completion support!) - i know it's depreciated but we have ABORT and
others still in ...
*) fixes small buglet with ALTER (TRIGGER|CLUSTER) ON autocomplete
(CLUSTER ON +<TAB> would produce CLUSTER ON ON - same for TRIGGER ON)
*) adapt to new SAVEPOINT syntax
*) fix incomplete Support for BEGIN [ TRANSACTION | WORK ]

and some random things I noticed that are either still missing or need
some thought:

*) provide a list of conversions after ALTER CONVERSION (?)
*) tabcomplete-support for ALTER SEQUENCE
*) add RENAME TO to ALTER TRIGGER
*) tab-completesupport for ALTER USER
*) fix ALTER (GROUP|DOMAIN|...) <sth> DROP - autocomplete
*) RENAME TO support for ALTER LANGUAGE <sth>
*) more complete support for COPY
*) more complete ALTER TABLE - support

Stefan