Attempt a fix to Cultist Secondary Objective, Survive Objective Scaling

- Formula for Cultists needed in the Survive/Escape objective is now 3 +
Total Players/4 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)
Merge pull request #2164 from dylanstrategie/Cult

Attempt a fix to Cultist Secondary Objective, Survive Objective Scaling