Fix citizen limit calculation v1.12 (#4229)
Fix citizen limit calculation. Now Calculates on building upgrade/destruction. Recalculates after colony load, instead of reading old values. Recruitment of additional guards over the citizen hut limit now works. Level 0 guard-buildings no longer count towards the limit.
Fix itemrack hooks beeing overwritten on load, backported from 1.14.
fix rack upgrade
update citizen limit upon all assigns/removes/building upgrade/destruction
fix TH UI issues