Fix a crash that occured if selecting a schema containing a domain.
Remove unused pgAgent options panel.
Fix links to the Options Dialogue pages in the docs.
Date picker controls returns a full timestamp by
default, which can cause inadvertent date changes
on jobs and role validty dates. Ignore the time part.
Fix the query editor behaviour with COPY

If you run something like:

copy (select * from pg_stat_activity) to stdout;

in the query editor, it will hang forever. The code in
pgQueryThread::execute() doesn't check for a PGRES_COPY_OUT result, and
calls PQgetResult() repeatedly. PQgetResult() will keep on returning
PGRES_COPY_OUT until the copy output is read with PQgetCopyData(), so it
gets stuck. COPY FROM STDIN has a similar problem.

This patch fixes that. For COPY TO STDOUT, it prints the first
100 rows to the message display. For COPY FROM STDIN, it throws an error.
Save new comments on already existing columns when editing a table

If I use the object browser context menu for an existing table and
choose "Properties...', I get a dialog that looks identical to dialog
for creating the table.  It allows me to add a new column to the table
just like in the table creation case, and it asks for a comment on the
new column.  But that comment gets thrown away.  The SQL tab reflects
the ALTER TABLE statement to add the column, but not the additional
statement to record the comment on that new column.

This patch fixes this. Unfortunately, it has a side-effect. When someone
changes a column property (but not the comment), and the column already had a
comment, it adds a COMMENT query with the old comment. So it's one useless
query. Not a big deal, and fixing this would be a huge work.

Per a report from Jeff Janes.