Debug: Introduce Dear ImGui interfaces

Introduce Dear ImGui to the CMakeBuild, allow building without it.

Add two debug interfaces : one FPS counter and frame time graph,
one map visualizer and editor.

CMakeLists.txt

@@ -11,8 +11,28 @@ if(NOT SFML_FOUND)
     message(FATAL_ERROR "SFML could not be found")
 endif()
 
-add_executable(raycasting main.cpp Player.cpp Player.h World.cpp World.h)
-
-target_link_libraries(raycasting
+set(LIBS
         sfml-window
-        sfml-graphics)
+        sfml-graphics)
+
+find_package(ImGui QUIET)
+find_package(ImGui-SFML QUIET)
+
+if(NOT ImGui_FOUND OR NOT ImGui-SFML_FOUND OR NO_IMGUI)
+    message("*Not* building with ImGui")
+else ()
+    message("Building with ImGui")
+    add_compile_definitions(IMGUI)
+    set(LIBS ${LIBS}
+            ImGui-SFML::ImGui-SFML)
+endif()
+
+add_compile_options(-Wall -Wextra)
+
+add_executable(raycasting
+        main.cpp
+        Player.cpp
+        World.cpp
+        )
+
+target_link_libraries(raycasting ${LIBS})