Fix bug where cultures would not expand to fill the entire continent
Add more spheres for gods
Rework city site placement to force cities to space out more, and disallow starting on ores
Various small refactors
QB no longer crashes; more minor refactors
Additional minor refactors for readability
Various small refactors
Split city map generator back into its own file
Move various common functions to new helpers.py file
Small refactors to deal with removal of helpers and city generation
Remove floodfill.py after its merge into helpers.py