Only notify on status change

[stoyle]

The gist of this feature request, have an option to only notify if test status changes. For instance if a test starts breaking, more tests break, or tests all pass after a fix.

This way of working is superior to me. They I don't get distracted when status has not changed. Tests just run in the background.

I would be happy to contribute some code, if you would like this feature.

Related, but unsure if possible, is to notify when test code does not compile. Will be happy to have a look at that as well.