suggestion: battle log cap

[florisjan]

When playing a scenario with a lot of raids, and setting pawns explode on death, I noticed that all the battle damage is logged. Under normal circumstances this is no problem, of course. The savegame in this situation grows to ridiculous sizes however due to the log lenght. Maybe it is an idea to cap the log lenght, I believe this will improve loading time in regular late games. Another factor is also the list of dead pawns. I understand they are stored for relations' sake, but maybe some sort of cleanup function might be a good idea, also for late game loading performance.