library now officially supports CORS out of the box #587

Hi Benjamin,

It has been a long time since I looked at the codebase where I use your library. For reference, the last version I used with my own custom modifications was based on commit 150e3d8.

I was actually planning to submit a minor edit today so your library could support CORS. However, looking at the recent modifications in your latest release, I noticed you have already implemented const WebSocketHttpHeaders& extraHeaders, which is exactly what was needed for CORS support.

I just compiled my codebase with your latest release, and it works perfectly. Since the library now officially supports this without needing manual patches to the .cpp and .h files, I won't need to submit a PR after all.

Thanks again for maintaining the library!