derive threat cost dynamically

src/lib/sim/CMakeLists.txt

@@ -9,6 +9,7 @@ SET(HDRS
     ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayout.h
     ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayoutBlueprint.h
     ${CMAKE_CURRENT_SOURCE_DIR}/ShipStatsCalculator.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ThreatCostCalculator.h
     ${CMAKE_CURRENT_SOURCE_DIR}/WaveSystem.h
     PARENT_SCOPE
 )
@@ -21,6 +22,7 @@ SET(SRCS
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildingSystem.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/EntityHitTest.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/ShipStatsCalculator.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ThreatCostCalculator.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/WaveSystem.cpp
     PARENT_SCOPE
 )