Unstable update

Some neat things in this one -

• Rival factions now exist properly in the overworld. All of your political dealings will carry over from one colony to another so long as you're loading up the same overworld.
  
• There can now be rival dwarf factions.
  
• Faction territories are per colony rather than per voxel. There's a toggle on the overworld screen to see them.
  
• Claiming a faction's land for your colony will piss them off.
  
• Claiming land costs money. You'll need to make a profit to expand.
  
• Trade envoys will carry far less cash and goods. Don't assume you can be instantly rich by being a murder hobo.
  
• New corporate policy is that employees must pay for goods they consume. They aren't happy, but all dwarves will now pay when they eat or drink.