add yaml serialization library

src/logic/scripting/lua/lua_engine.cpp

@@ -56,6 +56,7 @@ static void create_libs(State* L, StateType stateType) {
     openlib(L, "vec2", vec2lib);
     openlib(L, "vec3", vec3lib);
     openlib(L, "vec4", vec4lib);
+    openlib(L, "yaml", yamllib);
 
     if (stateType == StateType::SCRIPT) {
         openlib(L, "app", applib);