telnet character mode

[nelsonov]

In some telnet clients, it may be necessary to enable mode chacter in order to properly send control characters:

ctrl-]
telnet> mode character

It might be helpful to include this as a note in the README

Otherwise, I LOVE this. It's exactly what I was looking for. I needed to be able to connect at least two devices to a single ESP32. This saved me many days of development. Thank you.