Loan fixes, AI loan revamp, loans for Jews

- Fixed allow for take_medium_loan decision not including interest
(could result in repayment into bankruptcy)
- Fixed issue that caused every single AI character to promptly set the
flag loan_decisions
- Closed borrowing loopholes: no popes/patriarchs (other rel. heads OK),
no claimant adventurers, no rebels, no holy orders, no mercenaries, and
character must be a ruler regardless of yearly income.
- Allow Jews to take loans (they just can't 'Expel the Jewry' to escape
debt), incl. players
- AI will now actually take loans promptly when bankrupt, esp. if
personally at war (also uses a monthly randomizer to the chance in order
to add, on average, a small lag time between exhausting its funds and
resorting to a loan)
- AI will now consider repaying loans relatively promptly (ca. once
every 2 years), unless personally at war (while at war, ca. once every
10 years)
Loans: Fixes, annual payment event revamp, tracing support

- Fixed the potential clause in repay_medium_loan & repay_large_loan
preventing the new pay-by-halves functionality from working in those
cases.
- Updated ai_will_do war checks to include whether any liege is at war
and has raised the character's levies (in addition to a war in which the
character is actually an attacker or defender / war = yes) for all loan
decisions.
- Outfitted annual interest payment event with significant amount of
ai_chance modifiers to make a relatively intelligent decision about
whether to only make the yearly minimum payment(s) or to try to pay-back
as much as possible.
- Instrumented all instances of loan payment (interest), loan taken
(also as a result of the pay-by-halves strategy), and loan paid (or
expelled) events, categorized by loan tier, to allow optional tracing of
AI debt management behavior in the aggregate through, e.g., my batch
savegame series analyzer.
Rollback of loan tracing support

Meneth doesn't want the loan tracing support (via global flag setting)
to be included inline within a release candidate.  This commit removes
all of the tracing support.
Merge remote-tracking branch 'upstream/beta' into loans
Merge pull request #51 from zijistark/loans

Loan improvements sans the integrated tracing feature