Changed modifier batch calc to twice a month (on the 9th and 23rd), rather then every month (on the 21st); performance impact is utterly negligible and the gameplay improvement is noticable. Also tweaked difficulty events to check every/any_playable rather then just any/every, improving performance

Final update before MP game

Proper description added (I still have a poor opinion of the ideal lifespan of a Paradox employee)

IDK what I did here

Initial upload following THREE separate versions due to mod file issues