fix warning about session regenerated by Session class

When calling auth method in Session class, the session is regenerated
and PHP says headers are already sent but we don't care since this is
used in a CLI script. The fix is to disable cookies on session which is
checked by PHP when using the session_regenerate_id() function.
add missing variable needed to tasks update

I don't know yet if this should be needed by other tables. I'm just
focused on splitting the update process in several files in order to
organize and reduce the file.