message: Fix comments on FoodProduction class
diff: #include "Structure.h"
  /**
  -* \class PowerStructure
  -* \brief Virtual class for structures whose primary purpose is power production
  +* \class FoodProduction
  +* \brief Virtual class for structures whose primary purpose is agricultural production
  *
  -* \note PowerStructure is an abstract class
  +* \note FoodProduction is an abstract class
  */
  class FoodProduction : public Structure
  {
  