retirement age gate bug

generateslavemarket.js

I think the slave max age needs to be retirementAge-2

Some instances have retirementAge-1, which I think is not enough, with the 'celebrate birthdays, disable aging' setting.

With the default retirement age of 45, a slave age 44 will call up the retirement event on her birthday.

@Pregmodder @lowercasedonkey what do you think?