Repay half by event too
New CTA ambition icon from AnaxXiphos
Significant CTA chance tweaks, comment cleanup

Rolled-back CTA combat impulse chance base weight to -20% rather than
-40%.  Partially countervailing the increased chance for players is a
new flat bonus of 33% to the random weight given to all AI characters
with a CTA ambition selected.  A few more fine-grained tiers of martial
attribute correlation were also added.  I additionally
cleaned-up/clarified a few comment blocks. Small changes, significant
impact.