Three related patches on error handling.

Three patches:

-  Use file-truename consistently in cider-highlight-compilation-errors to avoid recognizing simplinked files as different.
- Add cider-auto-jump-to-error functionality. 
- Print cider error messages into minibuffer.  Most useful when `cider-show-error-buffer` is nil.  This particular behavior was there a month ago. I assume it's a regression that I don't see it anymore in the HEAD. 

Ok, I have dropped that part. I don't mind how it is implemented as long as I see the message;)