Wait for Karma to exit before allowing the JVM to exit.

[sinistral]

doo's invocation of Karma is non-blocking and sets a JVM shutdown hook that destroys the process on termination. To actually get the outcome of the run, we must wait for the process to complete before we exit.

[crisptrutski]

Thanks for the contribution! One thing that worries me about this approach is that it breaks the pattern of chaining various suites together as separate tasks. Will give this a spin before cutting the next release - perhaps existing terminal output makes the blocking clear, or we can add a log line ourselves. The premature exit has stumped many people I'm sure.