Suggestion: add option to prefix log messages with category

[Leopard501]

I often end up missing important log messages because they get buried under all the other messages. I suggest adding an option to prefix all log messages with the category they belong to. Something like:

[Research Queue] Master Craftsman has been researched.
[Combat] Your army was victorious! 5 soldiers died in the conflict.
[Minor Events] You discovered some tools buried in the ground.
[Achievements] Feat Unlocked! Gene Journeyman.