Mix Test Output Part Two

`This is how I fixed the tests over an umbrella project problem:

  mix test | tee test-logs.log
  echo "=== Unit Test Summary ==="
  grep "==>\| failure\|are no tests" test-logs.log
  rm test-logs.log

This way the last thing in the log file on the build server is a summary of the above tests.
It may include some false positives if you are logging too much, but it does include what is needed.