Making the AI care

The latest Itch build 634 makes explosions a little bit more colorful, but more importantly it gives friendly AIs a bit more agency.   

+All NPCs now have money.  

+Traders gain money every waypoint

+All NPCs gain money for killing enemies, and lose money for killing friends

+Friendly NPCs will go to a station and upgrade themselves when they have accumulated enough money

+Added Mercenaries, friendly NPCs which patrol between some number of planets, engaging any hostile NPCs.

+Friendly NPCs become temporarily unfriendly to any NPC or player that attacks them enough

+Traders now will fire on nearby enemies.  Hostile bots are not enemies by default, but if one attacks a trader the trader will consider them an enemy for a while.

+Mercenaries will choose a nearby enemy NPC, pursue and destroy it if there are any in radar range, continuing their patrol route if there are none.

+Kills by planetary collision or other non-weapon are now credited to the most recent attacker if there is a recent attacker.