Manually set some pointers to NULL after they are freed in case it prevents invalid dereferences.
Manually set some pointers to NULL after they are freed in case it prevents invalid dereferences.

git-svn-id: 80300035c0945e1dead713df30ec139394dadc1f@1220 1b2aedea-9eff-cdc0-263b-b87a75789507

cincodenada/editor-on-fire,cincodenada/editor-on-fire,cincodenada/editor-on-fire,cincodenada/editor-on-fire