Removed "login" name history; Deletion functions delete more data

Details:
- Removed "login" name history
- Deletion functions "delete_member" and "delete_private_data" delete more data
-- Fields "last_login" and "notify_email_lock_expiry" of table "member"
-- Final votes on open issues are deleted by "delete_member" function as well
- Version number changed to v1.2.0
- Update script