Modding: 
- "after [amount] turns" -> "after turn number [amount]"
- "before [amount] turns" -> "before turn number [amount]"
- "when number of [countable] is greater than [countable]" -> "when number of [countable] is more than [countable]"
- Clean improvement queue from improvements no longer in ruleset
- Better unique documentation

Fix performance problem for displaying air units in cities

Fix "edit existing trade" exploit

Fix console city add/remove building format - By SomeTroglodyte