twnlua: use stb_ds.h for enum conversions

apps/twnlua/game.c

@@ -12,6 +12,7 @@
 
 /* generated by bindgen.py */
 void bindgen_load_twn(lua_State *L);
+void bindgen_unload_twn(lua_State *L);
 
 
 /* require will go through physicsfs exclusively so that scripts can be in the data dir */
@@ -119,6 +120,7 @@ void game_tick(void) {
 
 void game_end(void) {
     State *state = ctx.udata;
+    bindgen_unload_twn(state->L);
     lua_close(state->L);
     free(state);
 }