HAL and scanners

[Martin Owens]

>
> Another solution should be to provide a tiny lib that do the hal<->sane
> mapping, maybe shiped with sane. Then hal might even ignore the backend.
> However, if hal can quickly determine the right backend, using a fdi,
> this will save some cpu cycle (i hate that probe dialog).
>

It's also far more flexable; allowing more information that may span
multiple scanner devices but use the same backend to exist outside of
the sane backend code would be a good way forwards.