Give Race_datum a preferred Map_type, to be used when placing a kingdom for that race.
Add a list of potential kingdom colors to Race_datum.
Replace Race::preferred_map_type with std::map<Map_type,int> Race::map_type_value.  Races can now have several different preferred map types of varying importance; even types they want to avoid!
World_map now tracks the uid of the various kingdoms in it.
Lots of work on Kingdom.  We now have a master list; one Kingdom will be created per Race, and it will be placed on the World_map.
Add trig_dist(), a function that returns real life distance (sqrt(dX^2 + dY^2)).
Make WORLD_MAP_SIZE slightly smaller.
In World_map::draw(), highlight tiles that belong to a Kingdom and display its information in the legend.
Init kingdoms after generating/loadin the world map.
Fix compile-time error.
Comment out bright kingdom colors; we're using them to highlight world map tiles, and bright-color highlighting doesn't work well on many terminals.
Fix the declaration of init_kingdoms().
In init_kingdoms(), assign proper uids that correspond to the index of Kingdoms.  Only try to assign a kingdom its race's main color if that color is not bright.  In Kingdom::place_in_world() don't automatically quit if we encounter a tile owned by another kingdom; instead, just assign a large point penalty.  When placing the kingdom, only claim tiles that are not already claimed, are not ocean, and are either valuable enough or close enough to the center of our kingdom.
Make kingdoms bigger.