actually pop to *idris-notes* buffer if there are warnings. if not, kill the *idris-notes* buffer
focus error when selecting in *idris-notes*
pop to repl only if it was freshly made
Merge pull request #69 from david-christiansen/interpreter-status

Show ! in the modeline while Idris is busy
Merge pull request #70 from hannesm/more-sane-error

More sane error
I like this nil better than the other one
Fix REPL completion

Now that idris-eval returns an optional second element, we needed to
examine the car to get the result.