Suggestion: Use elm-stuff as default target directory

[janwirth]

If we put things inside elm-stuff, we can clear the elm cache and the EVE cache at the same time and keep generated files out of version control with no additional configuration.

What are your thoughts on this?

[stoeffel]

Seems, reasonable. I don't know if that works with people who use elm-coverage (see https://github.com/stoeffel/elm-verify-examples/issues/65#issuecomment-478478704).

[gampleman]

Also a bit finicky since elm-test won't pick up those up by default.