better support for temporary objects

Instead of returning a session-specific schema name, return pg_temp
instead.  That way a command can be replayed elsewhere without being
dependent on the exact name of the replayer session's temp namespace.
report schema in pg_event_trigger_get_creation_commands

If the object is temporary, report "pg_temp".  This eases identification
of temporary objects.
Merge branch 'deparse' into bdr-deparse
ignore temp objects when queueing