classic & derivatives: Clean up StartUnits
classic ruleset part of the StartUnits clean up requested by ihnatus in https://www.hostedredmine.com/issues/870579
Should check if multiplayer and/or experimental rulesets are so close to classic in this respect that it makes sense to apply same changes to them.
Attached patch handles classic/multiplayer/(goldkeep/experimental)/webperimental, but also further touches civ2civ3/sandbox
classic ruleset part of the StartUnits clean up requested by ihnatus in https://www.hostedredmine.com/issues/870579
Should check if multiplayer and/or experimental rulesets are so close to classic in this respect that it makes sense to apply same changes to them.