Update ATEM_libstdc++.cpp

I'm sorry seems I replaced your original cpp and h file. I'm newbie to git and I thought changing file name with be saved as new file but I'm wrong. Can someone please help to revert? I know all changes is tracking by the system. And, my implementation base on socket so I still have a replacement library for the EthernetUDP going to be upload. I'm sorry to ask that how can I create new file? Or I should wait for the author to do this?