Make keyboard commands and compile errors show up in the debug log

In debugging a deeper issue (testem often not finding any tests, rerunning and/or reseting after having run tests, before you could see the output), I am adding some events to the debug log that help navigate what is going on.

(If you are cool with these, I'll probably trickle in a few other info level messages too, that pick up on when and why tests reran, which is what I am really digging for at the moment.)