[gta02-core] Tweaking the BOM processing

[Werner Almesberger]

Automating the whole thing was quite a bit of work. Now, let's reap
some sweet benefits.

For example, it's quite easy to run the whole process with different
inventories. This is particularly useful in our case, because the
inventory list from FIC contains ambiguities. Namely, the "Q'ty in
stock" field sometimes lists 0 items while the "Usable Q'ty" is
above zero.  

We can now process the inventory for an optimistic interpretation
(i.e., the "Usable Q'ty" can be trusted) or for a pessimistic
interpretation (i.e., the "Q'ty in stock" is all that's there).

The interpretation of the inventory is set with either

    cd bom
    make optimist

or

    cd bom
    make pessimist

This selection remains effective until the next "make spotless"
or "make optimist/pessimist". "make spotless all" defaults to the
pessimistic interpretation.

Another change we can make is what goes into the annotations. So
far, annotations used the parts list, i.e., for each component,
all possible parts were listed. We can now just show the parts
that will actually be used, i.e., from the order list. The choice
is made with

  make ANNOTATE=par gen

or

  make ANNOTATE=ord gen

The default is ANNOTATE=ord

I've uploaded new PDF and PS files for the optimistic
interpretation (*), with annotations for just the order list.

(*) Even if the reality is less pleasant, the optimistic version
    is what we want to review at the moment, because it contains
    more parts.

- Werner