The API `lv_refr_now` seems like not work in the master version!

Hi,
I just run the example lv_ex_cont_1, but it doesn’t work,It just displays all text directly after a certain time delay,the version is master

I’ve tested it and lv_refr_now() is working but the SDL dirver doesn’t update the window. It’s because it’s internal were rewritten to use a lv_task to refresh but in lv_refr_now only the display refresher task is called. Hence the window is not updated.

I’ve fixed it in lv_drivers.