Targetable weapons

[EXit_W0und]

The tag targetable=1 seems to be hard-coded so that everything with this weapon tag can be shot down by any weapon with interceptor=1.

I'd like to see this implemented in a similar way to the shield where there are different groups or types of weapon that an interceptor weapon can shoot at.

With this we could have nukes intercepted by anti nukes and maybe short range missiles being shot by laser - similar to anti missile ships in homeworld.

I realize it has the same effect as shields - but it would be a pretty funky alternative.