message: Remove largely pointless kill checks
  If the population component is zero, there will be zero growth towards
  death.
diff: @@ -134,8 +134,6 @@ void Population::spawnRetiree()
  void Population::killChildren(int morale, int nurseries)
  {
  - if (mPopulation.child <= 0) { return; }
  -
  mPopulationDeath.child += mPopulation.child;
  int divisor = moraleModifierTable[moraleIndex(morale)].mortalityRate + (nurseries * 10);
  @@ -156,8 +154,6 @@ void Population::killChildren(int morale, int nurseries)
  void Population::killStudents(int morale, int hospitals)
  {
  - if (mPopulation.student <= 0) { return; }
  -
  mPopulationDeath.student += mPopulation.student;
  int divisor = moraleModifierTable[moraleIndex(morale)].mortalityRate + (hospitals * 65);
  @@ -178,8 +174,6 @@ void Population::killStudents(int morale, int hospitals)
  void Population::killAdults(PopulationTable::Role role, int morale, int hospitals)
  {
  - if (mPopulation[role] <= 0) { return; }
  -
  mPopulationDeath[role] += mPopulation[role];
  int divisor = moraleModifierTable[moraleIndex(morale)].mortalityRate + 250 + (hospitals * 60);
  