We should add a --clearscreen flag that clears the console before a test run, for use with --watch. This would be handy for reporters other than "min" (which has this effect built in and can be used as an example for implementation). It can currently be done with a global before hook, but that's clumsier than a flag would be (you have to go out of your way to set it up so that you can choose to include it or not as easily as if it were a flag) and could work incorrectly in the unlikely edge case that you have other global before hooks printing stuff.

Inspired by @AshCoolman on Gitter.