The morning merge

Just miscellany, mainly:

- Jewish non-AI loan-taking fixed (potential of loan_decisions toggle didn't include jewish_group)
- Guarantee of 6 months following game start for player to decide whether to lead autonomy faction. I did this by simply halting the AI faction creation chance until 180 days had passed.  Since the choice is rather arbitrary anyway (aside from being more likely to not be a count when there are vassal dukes or kings around), we might as well give it to the player if eligible, should they want to take a more active role.  Ultimately, it'd be nice if the faction leader's bias didn't matter and agenda-setting was more direct, but the role matters a lot currently, and thus players might as well get the [guaranteed] choice of being faction leader if they want-- with all the risks that come with it.