Remove nuklear from engine

engine/tests/window_test.c

@@ -2,14 +2,27 @@
 #include <breeze.h>
 
 #include <raylib.h>
+#define CIMGUI_DEFINE_ENUMS_AND_STRUCTS
+#include <rlImGui.h>
+#include <cimgui.h>
+
+bool init(int *game) {
+    rlImGuiSetup(true);
+
+    return true;
+}
 
 void render(float dt, int *game) {
     ClearBackground(WHITE);
-    BeginDrawing();
-    EndDrawing();
+
+    rlImGuiBegin();
+    igShowDemoWindow(NULL);
+    rlImGuiEnd();
 }
 
 bool bzMain(BzAppDesc *appDesc, int argc, const char **argv) {
+    appDesc->init = (BzAppInitFunc) init;
     appDesc->render = (BzAppRenderFunc) render;
+
     return true;
 }