Add native instance and runtime statics

examples/cpp/main.cpp

@@ -5,8 +5,10 @@
 
 int main(int argc, char **argv)
 {
+    tribufu_api_initialize();
     const char *version = tribufu_api_get_user_agent();
     std::cout << version << std::endl;
     tribufu_free_string((char *)version);
+    tribufu_api_shutdown();
     return 0;
 }