Big internal change; MAXUTYPES & friends gone

[Stan Shebs]

For a long time, Xconq had a policy of statically sizing everything.
I originally did this to forestall debugging problems, but it's
become rather quaint, and limits flexibility.  So I've been on a
program to flush out arbitrary limits, and have just checked in
a massive (though conceptually simple) set of changes that
eliminate the old ceilings on the number of types of units, terrain,
materials, and advances.

There is one GDL-visible change, in that the supply (m) property
is no longer available in the unit-defaults form, since it would
have been complicated to keep it working.  But I doubt anybody
will notice!  Also, the code to grow the type property storage
isn't written yet, so tests with very large numbers of types will
fail.  Everything in the library seems to work OK, but there are
lots of code paths that use arrays of types, so beware.  The usual
symptom is a crash due to using a NULL pointer.

Stan