Rebel imprisonment fix

Fixed one issue with the siege imprisonment events that could lead to
rebels holding characters prisoner
Merge pull request #1 from MaestroUgo/master

Shouldn't be too hard to figure out.
Tiny change to siege code
Improved conversion AI

Made the AI smarter about who it'll send their court chaplain to convert
Fixed Østlanded being blue

Never made it into the master
Merge pull request #3 from Meneth/beta

Beta