[FIX] fix crlf to split response headers correctly

[leesnhyun]

OS : Windows 10, IE 11 (v 11.450.190410.0)

Sometimes CRLF of response header string is only '\n' at old browser (in my case, IE11).

To prevent unhandled exception, add some defense code by changing from "\r\n" to /\r|\n|\r\n/ .

[jonnyreeves]

Thanks for raising a fix for this @leesnhyun, I haven't touched this project for a long time but it does appear to have some unit tests, can you please confirm they are still passing and consider adding a new one to cover this regex? Thanks!