Since I am at work, it is hard for me to be of much help. I just went ahead and reverted it since we have dozens of high end events that rely heavily on $combat_state. I might have to start trying to read through the diffs of your merge to see if I can find anything though.

I just committed a fix for the COMBAT_EVENT signalling bug. That issue should be resolved now as of r888.

r888 also fixes the bug that bugged when you cancel a trade with a bot, even though I forgot to list that bug fix in the log.