Allow clicking the resource area to set worker locations
Draw tile hats, ruins, goods and so on in the city manager scenery panel; also only allow the city manager on our own cities
City Manager - show terrain (flat only for now), title and close button
Style the popup menu correctly
Build city manager background and activate it from popup menu
Add the special bonus production that you get on the main city tile
Allocate player colours; write city names and pop sizes on the overland map
Don't place cities on ruins