Basic telnet support?
**Is your feature request related to a problem? Please describe.**
I have a device on my intranet that accepts commands via telnet.  Some of the commands are simple toggles (no response), while others return state.  I'd like to use the http-switch but with single telnet commands to implement the toggle and state sniffing protocols.

**Describe the solution you'd like**

>     {
>       "accessory": "HTTP-SWITCH", "name": "TOGGLE1", "switchType": "stateful",
>       "onUrl": "telnet://xxx.xxx.xxx.xxx/ON-COMMAND",
>       "offUrl": "telnet://xxx.xxx.xxx.xxx/OFF-COMMAND",
>       "statusUrl": "telnet://xxx.xxx.xxx.xxx/STATE-REQUEST-COMMAND",
>       "statusPattern": "STATE-ON-PATTERN"
>     }   
> 

Where "ON-COMMAND", "OFF-COMMAND", and "STATE-REQUEST-COMMAND" are some ASCII sequences to pass via telnet.  For the statusUrl, the telnet server would return a status that should match "STATE-ON-PATTERN".

Thanks a ton in advance!
