Preliminary version of telnet using jline for command editing

Still a few things to fix:
- Initially there is some TELNET negotiation garbage in the buffer
- No script interrupt handling [ESC or ^C]
- Pressing ESC puts the terminal in an odd mode
- ScriptOutputStream does CR LF translation, which need not be done for ConsoleShell
Command line editing on TELNET mostly fixed -- tested on Mac and Linux telnet clients

Fixed outstanding problems mentioned in commit 3ff1bf8
Changed user abort to display a nicer message rather than throwing/logging an exception