[crossfire] New manhole archetype WIP (accepting help)

[Kevin R. Bulgrien]

I have committed a work-in-progress archetype for a multi-tile manhole.
To test the animation, and as a starter, the manhole is implemented as
a HOLE (object type 94) so that I could learn how to do animations and
could work off of a working example.

The archetype is a 64 x 64 bit graphic.  I have also include a .xcf
source file that is layered and has even more elements to produce
additional manholes once the animation problem is able to be
worked around.

My archetypes are based on arch/trunk/connect/Hole/pit.arc, but I had
to mangle the manhole_closed_1 archetype to get a working animation.

This is all documented in arch/trunk/dev/wip/manhole/README, and a test
case is set up as arch/trunk/dev/wip/manhole/world_105_115.patch.

It appears I may be the first to try creating a multi-tile HOLE, and
possibly the first to try to create any multi-tile connected animation.

I could use some help determining if I have borked the .arc file in some
way, or if perhaps the system just does not support such use of multi-
tile graphics in animations.  Any takers?

Kevin Bulgrien