Fixing multiple issues with popup display and auto-jumping

Moving from #851.

There is a new problem. Recent changes in `cider-nrepl` disabled stacktrace on warnings. This is unfortunate from auto-jumping perspective because in the case when there are both warnings and errors, the error stacktrace will popup but auto-jump will happen for a warning. I think stacktrace should be aware of the value of `cider-auto-jump-to-error`. To alliviate this issue I am setting this variable to `errors-only` by default.