Space age biter captivity

[DaleStan]

Closes #315; this treats ammo items that produce capture bots as placement items for the captured spawners, and reads the CaptureSpawnerTechnologyTrigger to display its information in the tooltips.

I ended up not reading CaptureRobotPrototype at all; it doesn't contain interesting information about what the capture robot does. The interesting information is the chain of triggers from an ammo item to a projectile entity to a capture bot entity, and also the (non-trigger) chain from the ammo item to the valid targets to the capture result.

I briefly considered trying to tie accessibility of captured spawners to both capture rockets and spawners, but (1) the dependency analyzer doesn't support "... or (A and B)" tests and (2) biter and spitter spawners are always accessible anyway.

[shpaass]

Thank you for the feature! That's takes dedication.