[2.0] Calva messes up CLJS nREPL session at connect

[PEZ]

So, this is pretty involved. I'll mainly add this issue so that I have something to track right now.

However. Something is not right with the connection process and it shows mostly for the CLJS sessions (I suspect it is something more fundmental, just not showing up as clearly for CLJ sessions).

Take a look at this project for some (too little, but anyway) context on this issue: https://github.com/PEZ/nrepl-test

[PEZ]

This seems to mostly be about a bug in piggieback, which is now fixed.