[crossfire] Useless rods

[Preston Crow]

I've noticed that some rods can never be used.  I'm under the impression 
that rods are implemented with a given number of spell points that 
regenerate quickly for casting the specified spell. Some spells require 
more points at higher levels.  In some cases, this results in a rod 
where the spell at that level requires more points than the rod has at 
full charge.

I'm playing on Metalforge, so it's possible that this has been addressed 
in newer code, but I would think there should be a check somewhere to 
either not generate these rods or to increase the maximum sp for a rod 
to match the sp required to cast if that is higher.

A good example is that a 'rod of turn undead' above level 53 will never 
work.  Likewise a 'rod of word of recall' above level 90 is useless.

I haven't checked heavy rods; I'm under the impression that they have a 
lot more sp, so it's unlikely to be a problem there.