fix 35

- replaced the [pri_a28_arch_strelok_2_walk] config with working one to
fix the final mission crash

- fixed trader progression in 'friend of stalkers' scenario

- increased giants attack power and slightly reduced its existance to
explosions

- nerfed poltergeist a little by:

* incresing the delay between item throws and reducing their power by
33%
* by slightly reducing their psy aura potence

- made some random changes to controler attack effector - need to check
in-game