Add 'resource' display mode, which highlights all non-woord resources on the map
First stage towards merchants being able to participate in multiple activities at once
Minor adjustments to economy agents
Tweaks to economy and resources to spread initial cities further apart
Remove some debug merchant messages
World is now divided into regions (for pathfinding) through a floodfill algorithm
Cultures now spread by simultaneous floodfill rather than 1-at-a-time expansion; all passable tiles in the playable region now contain a culture
Tweak culture spread and expand cultureal color set
Language screen now repurposed to Culture screen; shows information about culture as well as language
Tweaks to create slightly more interesting pantheons; tweaks to readability of celestial body descriptions