MondoFailure propagation + small fixes

1. On my windows machine a test would fail because it got \r\n for line break instead of \n. So I changed the test to use platform-independent line breaks
2. I found an issue where MondoFailures from dynamically registered subcommands are not propagated properly. This is because they are wrapped in the InvocationTargetException. I fixed this and added a unit test for it.