Attempted fix to Secondary Objective, scale Survive Objective

- Formula for Cultists needed in the Survive/Escape objective is now 3 + Total Players/5 instead of a base 5. For the smalles possible rounds (15 players) that's 6 cultists, all the way to highpop (70 players means 15 cultists)
- Some span
- Fix Sacrifice description. You need two acolytes, not three (2 + You)
- Tell people who somehow don't get their talisman to pray, muh immulsions
- Use pick() func instead of prob when picking objectives to try and fix the Second Objective cursed code

Addresses #2126 and #451

Proof that the players are okay with hardsauce Cult stuff : http://strawpoll.me/3158957/r (Favorite option was /4 instead of /5, but /5 about asks as an average)
Yeah its not clear its two -other- acolytes in this form.