fix 41

- implemented 'Update 18' from N.Aaroe

- fixed crash with 'error in stalker with visual (...)' by replacing the
xr_reach_task.script with one from version prior to v0.7.0.0

- disabled jup_sim_10 from a-life unitl quest with Mitay (hostage at
warehouses) is done

- prevented the squad which gives the hostage quest from getting out of
Yanov Station ever

- prevented Spartacus squad at Shevchenko from getting out of it after
the quest is done and they survive (Shevchenko itself still becomes
a-life active)

- prevented Bandit squad assaulting Shevchenko from becomming simulation
active after the assault is done (I think this part was the most
damaging to quest progression)