Fix the rounding of the values in the city ministats

[JPBergsma]

The function round() was used to round the values in the city stat minimenu. This function however rounds values ending in .5 to the nearest even integer. For determening the amount of generated food .5 is however rounded up. Therefore, I changed the rounding so values ending in .5 are always rounded up.

[SomeTroglodyte]

Welcome! I agree banker's rounding is for bankers, not logically thinking people. However, roundToInt is an alternative in the standard library that already does sensible rounding. Plus, it's consistent for negative values and yours isn't - surprise - toInt() is toward zero, it doesn't floor first. Not that we'll often see negative values here...

[JPBergsma]

Ah yes, I see your point. Gold values do go negative fairly often so that would definitely be a problem.
I have changed the rounding method.