tacnukes, fix core assistance stall, etc

- don't defend with siege units (arty, merl)
- turn corcrw into raider with defense fallback
- allow factories to build anything no matter how much assistance they
receive on summon
- make core build corcv like consul because core lacks consuls
- only stockpile and fire tacnukes at large groups of enemies
- register danger of attacking unit when fired upon
- add tacnukes
- seperate bombard targetting and nuke targetting (range check bombard)
- make sure to build *two* advanced cons