resolves #1393: kill children with more effort on SIGINT
fix throwing undefined/null now makes tests fail, fixes #1395
Fix test
Merge branch 'dasilvacontin-fix/throwUndefined'

* dasilvacontin-fix/throwUndefined:
  Fix test
  fix throwing undefined/null now makes tests fail, fixes #1395
Merge pull request #1401 from boneskull/issue/1393

resolves #1393: kill children with more effort on SIGINT
Print colored output only to a tty

Color output only if standard and error output are ttys.