message: Slaves cannot be captured before the first civ is able to adopt Colonialism
diff: @@ -176,6 +176,9 @@ def captureSlaves(winningUnit, losingUnit):
  if civ(winningUnit) == iAztecs:
  captureUnit(losingUnit, winningUnit, iAztecSlave, 35)
  + if players.major().none(lambda p: player(p).canDoCivics(iColonialism)):
  + return
  +
  elif civ(losingUnit) == iNative:
  if civ(winningUnit) not in lBioNewWorld or any(data.dFirstContactConquerors.values()):
  if player(winningUnit).isSlavery() or player(winningUnit).isColonialSlavery():
  