* Introduced economy exempt flagging

* Before adding traders

1. Make Cainan Economy and Stations
2. Make ITC Economy and Stations
	- Cainan Economy Completed
3. Add Weapons to Weapons Forges so they can be bought by the player
	- done for Ageirans
	- done for Cainans
4. Introduce economy-exempt stations
	- done.
	- use the flag 'exempt=true' when defining them in STATIONS.txt
5. Make ships purchasable by the player

Then start adding trading AI