[crossfire] map redo: more layers.

[Mark Wedel]

  The basic premise is to add more visible layers on the map, so more than 3 
objects can be displayed on a space.

  One other fix is to also more hard assign what layers objects show up in.  One 
problem with current protocol is that objects can move layers, and this is one 
thing that would be nice to fix.

  My basic idea would be to just assign what goes on the different layers, from 
bottom up:

0: map floor - since you can't see anything beneath the floor, this is the bottom.

1: building/buttons/whatever on top of floor, that player then stands on top of.
2: Same as 1 - I don't think there are actually cases were there are 2 objects, 
but I rather like to keep this open for expansion.

3-5: objects player may actually pick up/interract with

6: Player/monster
7: second monster - should really only show up if one of these is a multi space 
monster overlapping something else.

8-10: Flying objects - typically spells.

  The trickier part in all this is how to condense it down for the 3 objects for 
old protocol.  May idea would be to basically set up a table which says order of 
objects you are looking at.  The order would always be the same, but it may be 
something like:

0-6-8 (floor/creature/spell) - 1-9-2-3-5-10-7

  Basically, we look at those layers, and once we find 3 objects, we stop 
looking any further.

  This logic could also be useful for the new protocol - for bandwidth reasons, 
you may want to limit the number of layers to some level, say 5.  So it'd use 
this same mechanism to find the first 5 items on the space to send.