produce stacktrace buffer even when cider-popup-stacktraces is nil

[vspinu]

Fix the issues with stacktraces in #602. I have renamed the cider-popup-on-error because it wasn't really doing any popup and the name was conflicting with cider-popup-stacktraces.

[bbatsov]

Have a look at my final remarks regarding #602. I think we should combine all stacktrace variables into one. The current situation is more complex and more confusing than it needs to be.

[vspinu]

I have just implemented the proposed popup behavior.

[jeffvalk]

Typo: s/poped/popped/

[jeffvalk]

@Vitoshka Nice!

[bbatsov]

I think we should rename this to cider-show-stacktrace-buffer. (or something like that) I find the entire popup terminology a bit confusing.

[bbatsov]

Address my remarks and squash all commits into one. Your commit message should be with the format [Fix #602] Change .... See CONTRIBUTING.md for details. You should also add a changelog entry.

[bbatsov]

Perhaps those should be sub-bullets.

[bbatsov]

@Vitoshka Ping :-)

[vspinu]

Sorry, I have had a very busy week. Will address all of your comments in the following days.

[vspinu]

Hi. I have just commited a new patch.Should be fine this time.