D7 port of the recent D6 modifications

- #470470 by neilnz, use iLIKE for postgres selects.
- #558420 Accept trimmed titles in nodereference autocomplete validation to prevent title mismatch errors when title ends with space.
- security fixes in http://drupal.org/cvs?commit=380008 (SA : http://drupal.org/node/829566)