[Freeciv-Dev] (PR#6721) extended topologies base concept

["Marcelo Burda" <mburda@xxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=6721 >

my patch is based in xwrap_type and ywrap_type then all the code see it
normalize_map_ps() too. and make case if needed.

This is some complex and we make a init_topologie too set it easy
then the init_topologie can set a pointer too:
 normalize_map_pos = normalize_map_pos_quincuncial

and i can make separates fonction
 normalize_map_pos_flat()
 normalize_map_pos_cylindrical()
 normalize_map_pos_torus()
 etc without cast. this make best speed and more clean funcionts.
we can extend it for all topological funcions, eventualy we can make a 
cast on topology_id in less important fonction (map_clima, for 
generators).

Marcelo