message: Update PopulationPanel interface
diff: #include <NAS2D/Resources/Font.h>
  #include <NAS2D/Renderer/RectangleSkin.h>
  +#include <vector>
  class Population;
  @@ -19,13 +20,14 @@ public:
  void morale(int val) { mMorale = val; }
  void old_morale(int val) { mPreviousMorale = val; }
  - void residential_capacity(int m) { mResidentialCapacity = m; }
  + void residentialCapacity(int val) { mResidentialCapacity = val; }
  - /**
  - * \fixme This class/function is use to store residence capacity
  - * by the MapViewState. Probably not an appropriate place.
  - */
  - int capacity() const { return mCapacity; }
  + void addMoraleReason(const std::string& str, int val)
  + {
  + mMoraleChangeReasons.push_back(std::make_pair(str, val));
  + }
  +
  + void clearMoraleReasons() { mMoraleChangeReasons.clear(); }
  void update() override;
  @@ -35,12 +37,11 @@ private:
  const NAS2D::Image& mIcons;
  NAS2D::RectangleSkin mSkin;
  - Population* mPopulation = nullptr;
  + std::vector<std::pair<std::string,int>> mMoraleChangeReasons;
  - int mResidentialCapacity = 0;
  + Population* mPopulation = nullptr;
  int mMorale{ 0 };
  int mPreviousMorale{ 0 };
  -
  - int mCapacity{ 0 };
  + int mResidentialCapacity{ 0 };
  };
  