GDA (8.34.GDA-5863) Fix concurrent modification error in JythonServerFacade caused by by unsubscribing as a listener while updates are being sent out.

(Not an elegant fix)
GDA-5836 (8.34) Provided yaxis property on wrapped scans to set yaxis

Required as a work around because Scans within in scans do not set the user listed scannables correctly, and I had no time to wade in. Also a useful functionality though!
Minor improvement to the non-JLine telnet server: show prompt (">>>" or "...")
Allow disconnection from telnet/SSH server using Ctrl-D when JLine is turned on

Summary: the experience is *MUCH* better if you turn JLine on :-)

With JLine off, Ctrl-D is treated as part of a Jython command (and generally
messes things up). You still have to disconnect the client program manually
(Ctrl-] "quit" for telnet, Enter ~ . for SSH).

Additionally, for non-JLine SSH, you still can't see the characters you type
on-screen, as before.

With JLine on, things are now much better - if Ctrl-D is pressed, the socket
or session is closed, so the client gets disconnected. (Previously it would
just appear to hang, because the server had stopped processing data from the
client.)
Merge remote-tracking branch 'origin/8.34.GDA-5836'
Merge remote-tracking branch 'origin/gda-8.40'