Merge pull request #620 from jeffvalk/master

[Fix #615] Allow error/stacktrace display without middleware.
Adjust docstring
Add missing newline between welcome banner and version mismatch warning
Don't show version mismatch warning if cider-nrepl is not installed at all
Create the REPL buffer after we have the session's description
Remove unused no-repl-p param
Minor refactoring
[Fix #583] Avoid trying to decode the contents of the REPL buffer

I still have no idea what causes this problem, but at least people won't see
the error anymore.
Update copyright years
Fix a description
Code style
Refactor macroexpansion to use cider-last-sexp

cider-sexp-at-point works far less reliably, so using it is generally not
a very good idea.
Adjust docstring
Add missing newline between welcome banner and version mismatch warning
Don't show version mismatch warning if cider-nrepl is not installed at all
Create the REPL buffer after we have the session's description
Remove unused no-repl-p param
Minor refactoring
[Fix #583] Avoid trying to decode the contents of the REPL buffer

I still have no idea what causes this problem, but at least people won't see
the error anymore.
Update copyright years