Fix macroexpansion

[hugoduncan]

Macro expansion was giveing a "nrepl-netstring: Wrong type argument: stringp,
tidy" message. This calls symbol-name on
cider-macroexpansion-suppress-namespaces before passing it to
nrepl-send-request-sync.

[bbatsov]

This would require a middleware update as well - nil used to be encoded as an empty vector, now it won't be. I think if we changed the 3 config options to symbols - perhaps never, tidy and always. This would simplify the code a bit. The booleans made sense when this was on/off, but now - not so much.

[hugoduncan]

Having all cases be symbols definitely looks like it would be cleaner. I don't have time to fix this at the moment. @tsdh would you be able to take a look at it?

[bbatsov]

@tsdh You might even change the name of the defcustom to something like cider-macroexpansion-namespace-display. Seems to it makes more sense.

[tsdh]

@bbatsov, @hugoduncan I'm currently on a trip and won't return until Monday. If the issue is still there at that point in time, I'll take care of it.

[bbatsov]

OK. I'll probably won't have time for it today, but might be able to fix it tomorrow.